:root {
  color-scheme: light;
  --ink: #162019;
  --muted: #667067;
  --line: #d8ded6;
  --paper: #f5f3ec;
  --panel: #fffdfa;
  --panel-2: #ebe7dc;
  --accent: #3b6f5b;
  --danger: #a84f3d;
  --shadow: 0 18px 50px rgba(35, 43, 34, 0.1);
  font-family: Avenir Next, Optima, Candara, Segoe UI, sans-serif;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100vh;
  overflow: hidden;
}

body {
  margin: 0;
  background:
    linear-gradient(90deg, rgba(22, 32, 25, 0.045) 1px, transparent 1px),
    linear-gradient(rgba(22, 32, 25, 0.04) 1px, transparent 1px),
    var(--paper);
  background-size: 28px 28px;
  background-attachment: fixed;
  color: var(--ink);
}

#app {
  height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input,
textarea {
  font: inherit;
}

.shell {
  display: grid;
  grid-template-columns: var(--sidebar-width, 290px) 6px minmax(0, 1fr);
  height: 100vh;
  overflow: hidden;
}

.sidebar {
  height: 100vh;
  padding: 22px 18px;
  background: rgba(255, 253, 250, 0.92);
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 24px;
  overflow-y: auto;
  overflow-x: hidden;
}

.sidebar-head {
  display: flex;
  align-items: center;
  gap: 8px;
  justify-content: space-between;
}

.sidebar-toggle {
  border: 1px solid var(--line);
  background: var(--paper);
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  cursor: pointer;
  font-weight: 700;
  font-size: 14px;
  color: var(--muted);
  flex-shrink: 0;
}

.sidebar-toggle:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.brand .brand-text { display: block; }
.brand .brand-text strong { display: block; }

.nav-course .nav-icon,
.nav-tool .nav-icon,
.nav-dashboard .nav-icon,
.nav-divider .nav-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  flex-shrink: 0;
  color: var(--muted);
}

.nav-icon svg {
  width: 20px;
  height: 20px;
  display: block;
}

.course-icon svg {
  width: 22px;
  height: 22px;
}

.nav-dashboard.active .tool-icon,
.nav-tool.active .tool-icon {
  color: var(--ink);
}

.flashcards-icon { color: #365f8f; }
.mistakes-icon { color: #a84f3d; }
.mocks-icon { color: #755a9b; }

.nav-dashboard,
.nav-tool {
  display: flex !important;
  align-items: center;
  gap: 10px;
}

/* Collapsed-sidebar mode: hide all text, keep icons */
:root[data-sidebar-collapsed="true"] .sidebar {
  padding: 22px 8px;
}

:root[data-sidebar-collapsed="true"] .nav-label,
:root[data-sidebar-collapsed="true"] .brand-text,
:root[data-sidebar-collapsed="true"] .state-card,
:root[data-sidebar-collapsed="true"] .nav-course small,
:root[data-sidebar-collapsed="true"] .nav-divider {
  display: none;
}

:root[data-sidebar-collapsed="true"] .nav-course,
:root[data-sidebar-collapsed="true"] .nav-tool,
:root[data-sidebar-collapsed="true"] .nav-dashboard {
  justify-content: center;
  padding: 10px 6px;
}

:root[data-sidebar-collapsed="true"] .brand {
  justify-content: center;
  gap: 0;
}

:root[data-sidebar-collapsed="true"] .sidebar-head {
  flex-direction: column;
  gap: 8px;
}

/* ----- Resize handles ----- */
.resize-handle {
  position: relative;
  background: transparent;
  z-index: 5;
}

.resize-handle.vertical-handle {
  cursor: col-resize;
  width: 6px;
  align-self: stretch;
}

.resize-handle.vertical-handle::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: -2px;
  right: -2px;
}

.resize-handle.vertical-handle::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 2px;
  height: 30px;
  background: var(--line);
  border-radius: 1px;
  opacity: 0;
  transition: opacity 0.15s, background 0.15s;
}

.resize-handle.vertical-handle:hover::after,
.resize-handle.vertical-handle:active::after {
  opacity: 1;
  background: var(--accent);
  height: 60px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  background: var(--ink);
  color: var(--paper);
  font-weight: 800;
  letter-spacing: 0;
}

.brand strong,
.nav-course strong {
  display: block;
}

.brand small,
.nav-course small,
.state-card small {
  color: var(--muted);
}

nav {
  display: grid;
  gap: 8px;
}

.nav-dashboard,
.nav-course {
  border: 1px solid transparent;
  padding: 10px 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-dashboard.active,
.nav-course.active,
.nav-dashboard:hover,
.nav-course:hover {
  background: var(--panel-2);
  border-color: var(--line);
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex: 0 0 auto;
}

.state-card {
  margin-top: auto;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 12px;
  display: grid;
  gap: 6px;
}

code {
  font-family: SFMono-Regular, Consolas, Liberation Mono, monospace;
  font-size: 0.84em;
  color: #4b5a4f;
}

.content {
  padding: 28px;
  height: 100vh;
  overflow-y: auto;
  overflow-x: hidden;
}

.chapter-content {
  padding: 0;
  height: 100vh;
  overflow: hidden;
}

.chapter-shell .sidebar {
  overflow: hidden;
}

.hero,
.course-hero {
  min-height: 230px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  padding: 30px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 190px;
  align-items: end;
  gap: 24px;
}

.course-hero {
  border-top: 6px solid var(--accent);
}

.eyebrow {
  margin: 0 0 8px;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 12px;
  font-weight: 800;
  color: var(--muted);
}

h1,
h2,
h3,
h4,
p {
  margin-top: 0;
}

h1 {
  max-width: 820px;
  margin-bottom: 14px;
  font-family: Georgia, Iowan Old Style, serif;
  font-size: clamp(38px, 5vw, 72px);
  line-height: 0.96;
  letter-spacing: 0;
}

.hero-copy {
  max-width: 650px;
  color: var(--muted);
  font-size: 18px;
}

.hero-meter {
  aspect-ratio: 1;
  border: 1px solid var(--ink);
  display: grid;
  place-items: center;
  text-align: center;
  padding: 18px;
  background: var(--paper);
}

.hero-meter span {
  display: block;
  font-size: 52px;
  font-weight: 800;
}

.hero-meter small {
  color: var(--muted);
}

.course-grid {
  margin: 14px 0 24px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
}

/* "Courses" / "Manage courses" header row above the grid */
.course-section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-top: 26px;
}

.course-section-head h2 {
  font-family: Georgia, "Iowan Old Style", serif;
  font-size: 22px;
  margin: 0;
}

.course-section-head.archived-head {
  margin-top: 20px;
}

.course-section-head.archived-head h3 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0;
}

.course-section-head.archived-head h3 small {
  background: var(--panel-2);
  padding: 1px 7px;
  margin-left: 4px;
}

.course-card {
  --accent: #3b6f5b;
  min-height: 205px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 5px solid var(--accent);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.course-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.course-card.is-managing:hover {
  transform: none;
  box-shadow: none;
}

.course-card.is-archived {
  opacity: 0.6;
  border-top-style: dashed;
}

.course-card.is-archived:hover {
  opacity: 1;
}

.course-grid-archived .course-card {
  min-height: 0;
}

/* Manage-mode control bar inside a course card */
.course-card-manage {
  margin-top: auto;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding-top: 10px;
  border-top: 1px dashed var(--line);
}

.course-card-manage .course-move {
  width: 32px;
  padding: 4px 0;
  text-align: center;
}

.course-card-manage .course-open {
  margin-left: auto;
}

/* Sidebar archived section */
.nav-archived-toggle {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  border: 0;
  background: transparent;
  cursor: pointer;
  font: inherit;
  padding: 8px 12px;
  color: var(--muted);
}

.nav-archived-toggle:hover { color: var(--ink); }

.nav-archived-toggle .nav-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 700;
}

.nav-archived-list .nav-course { opacity: 0.7; }
.nav-archived-list .nav-course:hover { opacity: 1; }

:root[data-sidebar-collapsed="true"] .nav-archived-toggle { justify-content: center; padding: 8px 6px; }

.course-card-top,
.panel-head,
.block-title,
.section-heading,
.todo-title-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.course-card h2 {
  font-size: 24px;
  line-height: 1.05;
}

.course-card p,
.course-card small {
  color: var(--muted);
}

.bar,
.mini-bar {
  width: 100%;
  height: 8px;
  background: #dfe3dc;
  overflow: hidden;
  margin-top: auto;
}

.mini-bar {
  height: 5px;
  margin: 0;
}

.bar span,
.mini-bar span {
  display: block;
  height: 100%;
  background: var(--accent);
}

.panel,
.category-section {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 22px;
}

.day-list,
.item-list {
  display: grid;
  gap: 12px;
}

.day-block {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.block-meta {
  display: grid;
  align-content: start;
  gap: 4px;
}

.block-meta span,
.block-body p,
.todo-meta,
.deliverable,
.empty {
  color: var(--muted);
}

.pill,
.copy-id,
.kb-link {
  border: 1px solid var(--line);
  padding: 6px 9px;
  background: var(--paper);
  color: var(--ink);
}

.compact-list {
  display: grid;
  gap: 6px;
  margin-top: 12px;
}

.compact-item {
  display: flex;
  align-items: center;
  gap: 10px;
  background: #f7f5ef;
  border: 1px solid var(--line);
  padding: 9px;
}

.compact-item.done {
  opacity: 0.7;
}

.compact-item.done strong,
.todo-card.done h3 {
  text-decoration: line-through;
}

.compact-item small {
  display: block;
  color: var(--muted);
}

.mastery-picker {
  display: inline-flex;
  gap: 3px;
  align-items: center;
}

.mastery-picker.compact {
  flex: 0 0 auto;
}

.mastery-picker.full {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 4px;
  width: 100%;
}

.mastery-btn {
  width: 24px;
  height: 24px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  font-weight: 700;
  cursor: pointer;
  padding: 0;
  display: grid;
  place-items: center;
}

.mastery-picker.full .mastery-btn {
  width: auto;
  height: 30px;
}

.mastery-btn:hover {
  border-color: var(--ink);
}

.mastery-btn.lvl-0.active { background: #e5e3da; color: var(--muted); border-color: var(--muted); }
.mastery-btn.lvl-1.active { background: #f3e2c8; color: #6e4f1f; border-color: #c79248; }
.mastery-btn.lvl-2.active { background: #e9dbb2; color: #5e4a1e; border-color: #b08846; }
.mastery-btn.lvl-3.active { background: #c4dec8; color: #1f4d2a; border-color: #4f8a5e; }
.mastery-btn.lvl-4.active { background: #3b6f5b; color: var(--paper); border-color: #1f4d2a; }

.todo-mastery {
  display: grid;
  gap: 6px;
  align-content: start;
}

.todo-mastery .mastery-label {
  font-weight: 700;
  color: var(--ink);
}

.todo-mastery .mastery-when {
  color: var(--muted);
}

.legend {
  display: block;
  margin-top: 6px;
  line-height: 1.4;
}

.coverage {
  margin: 24px 0;
}

.coverage-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 8px;
}

.coverage-table th,
.coverage-table td {
  text-align: left;
  padding: 9px 10px;
  border-bottom: 1px solid var(--line);
  vertical-align: middle;
  font-size: 14px;
}

.coverage-table th {
  font-weight: 700;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 11px;
}

.coverage-table tr.uncovered td {
  color: var(--danger);
  background: rgba(168, 79, 61, 0.06);
}

.coverage-table .mini-bar {
  min-width: 100px;
}

.item-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

.item-pill {
  border: 1px solid var(--line);
  padding: 3px 7px;
  background: #f4f1e8;
  color: #4f594f;
  font-size: 12px;
}

.item-pill.done {
  background: #dfeadf;
  color: #2c4b34;
  text-decoration: line-through;
}

.chapter-pill {
  border-color: var(--accent) !important;
  background: rgba(59, 111, 91, 0.08) !important;
  color: #2c4b34 !important;
  font-weight: 600;
}

.review-log {
  margin-top: 14px;
  border-top: 1px dashed var(--line);
  padding-top: 12px;
}

details.review-log > summary {
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 14px;
  list-style: none;
  user-select: none;
}

details.review-log > summary::-webkit-details-marker {
  display: none;
}

details.review-log > summary::before {
  content: '▸';
  display: inline-block;
  transition: transform 0.15s;
  font-size: 10px;
  color: var(--muted);
}

details.review-log[open] > summary::before {
  transform: rotate(90deg);
}

details.review-log > summary .log-count {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 1px 7px;
  border-radius: 999px;
  font-size: 12px;
  color: var(--muted);
  margin-right: auto;
}

details.review-log .review-events,
details.review-log .empty-log {
  margin-top: 10px;
}

.log-btn {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 4px 8px;
  cursor: pointer;
  font-size: 12px;
}

.log-btn:hover {
  border-color: var(--ink);
}

.review-events {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 4px;
}

.review-events li {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  font-size: 13px;
  padding: 5px 8px;
  background: #f7f5ef;
  border: 1px solid var(--line);
}

.review-events .when {
  font-weight: 600;
  min-width: 70px;
}

.review-events .kind {
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-size: 11px;
  border: 1px solid var(--line);
  padding: 1px 5px;
  background: var(--paper);
}

.review-events .delta {
  font-weight: 700;
  color: var(--accent);
}

.review-events .score {
  font-weight: 700;
}

.review-events .note {
  color: var(--muted);
  font-style: italic;
}

.empty-log {
  color: var(--muted);
  font-style: italic;
  margin: 0;
}

.nav-course strong em {
  font-style: normal;
  font-weight: 400;
  color: var(--muted);
  margin-left: 6px;
  letter-spacing: 0.04em;
}

.course-card-top em {
  font-style: normal;
  font-weight: 600;
  color: var(--muted);
  margin-left: 4px;
}

.compact-link {
  display: block;
  flex: 1;
  min-width: 0;
  cursor: pointer;
  padding: 2px 4px;
  margin: -2px -4px;
}

.compact-link:hover {
  background: rgba(0, 0, 0, 0.04);
}

.compact-link small {
  display: block;
  color: var(--muted);
}

.coverage-table tr.clickable {
  cursor: pointer;
}

.coverage-table tr.clickable:hover td {
  background: rgba(0, 0, 0, 0.025);
}

.coverage-table tr.uncovered.clickable:hover td {
  background: rgba(168, 79, 61, 0.12);
}

.item-toolbar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 18px 0 12px;
  align-items: center;
}

.item-toolbar input,
.item-toolbar select,
.item-toolbar button {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 8px 10px;
  color: var(--ink);
  font-size: 14px;
}

.item-toolbar input.item-search {
  flex: 1 1 240px;
  min-width: 180px;
}

.item-toolbar .clear-btn {
  cursor: pointer;
  background: var(--paper);
}

.item-toolbar .clear-btn:hover {
  border-color: var(--ink);
}

.chapter-loading {
  padding: 60px 30px;
  text-align: center;
  color: var(--muted);
  font-size: 16px;
}

.chapter-loading.error {
  color: var(--danger);
}

.chapter-grid {
  display: grid;
  grid-template-columns: var(--toc-width, 240px) 6px minmax(0, 1fr) 6px var(--rail-width, 380px);
  gap: 12px;
  height: 100vh;
  min-height: 0;
  padding: 22px 26px;
  align-items: stretch;
  overflow: hidden;
}

:root[data-rail-collapsed="true"] .chapter-grid {
  grid-template-columns: var(--toc-width, 240px) 6px minmax(0, 1fr) 0 36px;
}

:root[data-toc-collapsed="true"] .chapter-grid {
  grid-template-columns: 36px 0 minmax(0, 1fr) 6px var(--rail-width, 380px);
}

:root[data-toc-collapsed="true"][data-rail-collapsed="true"] .chapter-grid {
  grid-template-columns: 36px 0 minmax(0, 1fr) 0 36px;
}

.chapter-toc {
  position: relative;
  height: 100%;
  min-height: 0;
  overflow: hidden;
  padding: 14px 12px;
  border: 1px solid var(--line);
  background: var(--panel);
  font-size: 14px;
}

.rail-collapse-btn {
  position: absolute;
  top: 8px;
  right: 6px;
  width: 22px;
  height: 22px;
  border: 1px solid var(--line);
  background: var(--paper);
  cursor: pointer;
  display: grid;
  place-items: center;
  font-weight: 700;
  color: var(--muted);
  font-size: 14px;
  z-index: 2;
  padding: 0;
}

.rail-collapse-btn:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.rail-collapse-btn.rail-side {
  left: 6px;
  right: auto;
}

.rail-collapsible {
  display: flex;
  flex-direction: column;
  gap: 14px;
  height: 100%;
  min-height: 0;
}

.chapter-toc > .rail-collapsible {
  padding-top: 18px;
  overflow-x: hidden;
  overflow-y: auto;
  scrollbar-gutter: stable;
  padding-right: 4px;
}

.chapter-rail > .rail-collapsible {
  flex: 1 1 auto;
  min-height: 0;
  padding-left: 24px;
}

:root[data-toc-collapsed="true"] .chapter-toc {
  align-self: start;
  height: auto;
  min-height: 0;
  padding: 0;
  overflow: hidden;
  border: 0;
  background: transparent;
}

:root[data-toc-collapsed="true"] .chapter-toc > .rail-collapsible {
  display: none;
}

:root[data-toc-collapsed="true"] .chapter-toc .rail-collapse-btn {
  position: static;
  margin: 0 auto;
  background: var(--panel);
  box-shadow: 0 8px 22px rgba(35, 43, 34, 0.08);
}

:root[data-rail-collapsed="true"] .chapter-rail {
  align-self: start;
  padding: 0;
  overflow: hidden;
  height: auto;
  min-height: 0;
}

:root[data-rail-collapsed="true"] .chapter-rail > .rail-collapsible {
  display: none;
}

:root[data-rail-collapsed="true"] .chapter-rail .rail-collapse-btn {
  position: static;
  margin: 0 auto;
  background: var(--panel);
  box-shadow: 0 8px 22px rgba(35, 43, 34, 0.08);
}

:root[data-toc-collapsed="true"] .chapter-grid .resize-handle[data-resize="toc"],
:root[data-rail-collapsed="true"] .chapter-grid .resize-handle[data-resize="rail"] {
  pointer-events: none;
  opacity: 0.3;
}

.chapter-toc h4 {
  margin: 14px 0 8px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.chapter-toc h4:first-child {
  margin-top: 0;
}

.toc-back {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 8px 10px;
  margin-bottom: 12px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  font-size: 13px;
  font-weight: 700;
  text-align: left;
  border-left: 3px solid var(--accent);
  min-width: 0;
}

.toc-back svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  color: var(--accent);
}

.toc-back em {
  font-style: normal;
  font-weight: 500;
  color: var(--muted);
}

.toc-back span {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.toc-back:hover {
  background: var(--panel);
  border-color: var(--accent);
}

.chapter-toc ol {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 2px;
}

.chapter-toc li a {
  display: block;
  padding: 4px 6px;
  border-left: 2px solid transparent;
  color: var(--ink);
}

.chapter-toc li.lvl-3 a {
  padding-left: 18px;
  color: var(--muted);
  font-size: 13px;
}

.chapter-toc li a:hover {
  border-left-color: var(--accent);
  background: var(--paper);
}

.chapter-toc .toc-jump {
  display: block;
  margin-top: 10px;
  padding: 6px 8px;
  border: 1px dashed var(--line);
  background: var(--paper);
  font-weight: 600;
}

.chapter-main {
  min-width: 0;
  min-height: 0;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  padding-bottom: 58px;
  scroll-padding-top: 16px;
}

.chapter-rail {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 14px;
  height: 100%;
  min-height: 0;
  overflow: hidden;
}

.rail-card {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 14px;
  flex-shrink: 0;
}

.rail-card h4 {
  margin: 0 0 8px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.rail-meta {
  color: var(--muted);
  font-size: 12px;
  margin-bottom: 8px;
}

.rail-items {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 8px;
}

.rail-item {
  border: 1px solid var(--line);
  padding: 8px;
  background: var(--paper);
  display: grid;
  gap: 6px;
  font-size: 13px;
}

.rail-item.done {
  opacity: 0.75;
}

.rail-item.done strong {
  text-decoration: line-through;
}

.rail-item-link {
  display: grid;
  gap: 2px;
}

.rail-item-link strong {
  font-size: 13px;
}

.rail-item-link small {
  color: var(--muted);
  font-size: 11px;
}

.rail-kb-link {
  display: block;
  padding: 8px 10px;
  border: 1px solid var(--line);
  background: var(--paper);
  font-size: 12px;
  word-break: break-all;
}

.chat-panel {
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1 1 0;
  min-height: 0;
  overflow: hidden;
}

.chat-messages {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 10px;
  flex: 1 1 0;
  min-height: 0;
  max-height: 60vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 13px;
  line-height: 1.5;
}

.chat-msg .chat-body {
  overflow-wrap: break-word;
  word-break: break-word;
}

.chat-msg.chat-assistant .chat-body h1,
.chat-msg.chat-assistant .chat-body h2,
.chat-msg.chat-assistant .chat-body h3,
.chat-msg.chat-assistant .chat-body h4 {
  font-size: 13px;
  margin: 8px 0 4px;
  font-weight: 700;
  color: var(--ink);
}

.chat-msg.chat-assistant .chat-body table {
  display: block;
  width: 100%;
  max-width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
  margin: 8px 0;
  font-size: 12px;
}

.chat-msg.chat-assistant .chat-body th,
.chat-msg.chat-assistant .chat-body td {
  border: 1px solid var(--line);
  padding: 4px 6px;
  text-align: left;
  vertical-align: top;
}

.chat-msg.chat-assistant .chat-body th {
  background: var(--paper);
  font-weight: 700;
  color: var(--muted);
  text-transform: none;
  font-size: 11px;
}

.chat-msg.chat-assistant .chat-body blockquote {
  border-left: 2px solid var(--accent);
  margin: 6px 0;
  padding: 2px 8px;
  color: var(--muted);
  font-size: 12px;
}

.chat-msg.chat-assistant .chat-body .katex-display {
  margin: 6px 0;
  overflow-x: auto;
  overflow-y: hidden;
}

.chat-msg.chat-assistant .chat-body .katex {
  font-size: 1em;
}

.chat-empty {
  color: var(--muted);
  font-style: italic;
  margin: 0;
}

.chat-msg {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.chat-msg .chat-role {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  font-weight: 700;
}

.chat-msg.chat-user .chat-body {
  background: #eef0ea;
  border: 1px solid var(--line);
  padding: 8px 10px;
  border-radius: 2px;
}

.chat-msg.chat-assistant .chat-body {
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  padding: 8px 10px;
}

.chat-msg.chat-assistant .chat-body p {
  margin: 0 0 6px;
}

.chat-msg.chat-assistant .chat-body p:last-child {
  margin: 0;
}

.chat-msg.chat-assistant .chat-body pre {
  font-size: 11px;
  padding: 6px 8px;
  max-height: 200px;
  overflow: auto;
  margin: 6px 0;
}

.chat-msg.chat-assistant .chat-body code {
  font-size: 11px;
}

.chat-msg.chat-assistant .chat-body ul,
.chat-msg.chat-assistant .chat-body ol {
  padding-left: 18px;
  margin: 6px 0;
}

.chat-thinking {
  color: var(--muted);
  font-style: italic;
  font-size: 12px;
  padding: 4px 0;
}

.chat-form {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.chat-input {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 8px 10px;
  font-family: inherit;
  font-size: 13px;
  resize: vertical;
  min-height: 50px;
}

.chat-actions {
  display: flex;
  gap: 6px;
}

.chat-send {
  flex: 1;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--paper);
  padding: 8px 12px;
  font-weight: 600;
  cursor: pointer;
  font-size: 13px;
}

.chat-send:disabled {
  background: var(--muted);
  border-color: var(--muted);
  cursor: wait;
}

.chat-clear {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 8px 12px;
  font-size: 12px;
  cursor: pointer;
  color: var(--muted);
}

.chat-clear:hover {
  color: var(--ink);
}

.chapter-hero {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 6px solid var(--accent);
  padding: 22px 26px;
  box-shadow: var(--shadow);
  margin-bottom: 18px;
}

/* ----- Sidebar search trigger ----- */
.sidebar-search-trigger {
  display: flex;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 10px 12px;
  cursor: pointer;
  font: inherit;
  color: var(--muted);
  width: 100%;
  text-align: left;
}

.sidebar-search-trigger:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.sidebar-search-trigger .search-icon {
  font-size: 13px;
  color: inherit;
}

.sidebar-search-label {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex: 1;
  font-size: 13px;
}

.sidebar-search-label small {
  color: var(--muted);
  font-size: 11px;
  font-family: SFMono-Regular, Consolas, Liberation Mono, monospace;
}

/* Collapsed sidebar: icon only, no label */
:root[data-sidebar-collapsed="true"] .sidebar-search-trigger {
  justify-content: center;
  padding: 10px 6px;
}

:root[data-sidebar-collapsed="true"] .sidebar-search-label {
  display: none;
}

/* ----- Search popup (centered modal) ----- */
.search-overlay {
  position: fixed;
  inset: 0;
  background: rgba(22, 32, 25, 0.32);
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 12vh 24px 24px;
  z-index: 200;
  backdrop-filter: blur(2px);
}

.search-popup {
  width: 100%;
  max-width: 720px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 0 30px 60px rgba(22, 32, 25, 0.32);
  display: flex;
  flex-direction: column;
  max-height: 70vh;
}

.search-popup-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
}

.search-popup-icon {
  font-size: 16px;
  color: var(--muted);
}

.search-popup-input {
  flex: 1;
  border: 0;
  outline: 0;
  background: transparent;
  font-size: 16px;
  color: var(--ink);
}

.search-popup-input::placeholder {
  color: var(--muted);
}

.search-popup-clear,
.search-popup-close {
  border: 0;
  background: transparent;
  color: var(--muted);
  font-size: 18px;
  line-height: 1;
  cursor: pointer;
  padding: 4px 6px;
}

.search-popup-clear:hover,
.search-popup-close:hover {
  color: var(--ink);
}

.search-popup-courses {
  display: flex;
  gap: 6px;
  padding: 8px 14px;
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
  background: var(--paper);
}

.search-popup-course-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 4px 10px;
  cursor: pointer;
  font: inherit;
  font-size: 12px;
  color: var(--muted);
}

.search-popup-course-pill em {
  font-style: italic;
  color: var(--muted);
}

.search-popup-course-pill:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.search-popup-course-pill.is-active {
  border-color: var(--accent);
  color: var(--ink);
  background: var(--paper);
}

.search-popup-results {
  flex: 1 1 auto;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.search-popup-result {
  text-align: left;
  background: transparent;
  border: 0;
  border-bottom: 1px solid var(--line);
  padding: 10px 16px;
  cursor: pointer;
  font: inherit;
  color: var(--ink);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.search-popup-result:last-child {
  border-bottom: 0;
}

.search-popup-result:hover {
  background: var(--paper);
}

.search-popup-result.is-selected {
  background: var(--paper);
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.search-popup-result-head {
  font-size: 13px;
}

.search-popup-result-heading {
  color: var(--muted);
}

.search-popup-result-snippet {
  font-size: 12px;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.search-popup-status {
  padding: 16px;
  font-size: 13px;
  color: var(--muted);
}

.search-popup-status.error {
  color: var(--danger);
}

.search-popup-status.empty {
  font-style: italic;
}

.search-popup-foot {
  display: flex;
  gap: 16px;
  padding: 8px 14px;
  border-top: 1px solid var(--line);
  background: var(--paper);
  font-size: 11px;
  color: var(--muted);
}

.search-popup-foot kbd {
  display: inline-block;
  padding: 1px 5px;
  background: var(--panel);
  border: 1px solid var(--line);
  font-family: SFMono-Regular, Consolas, Liberation Mono, monospace;
  font-size: 10px;
  color: var(--ink);
  margin-right: 2px;
}

/* ----- Course chapters section in chapter-toc ----- */
.course-chapters-section {
  border: 1px solid var(--line);
  background: var(--paper);
  margin: 6px 0 14px;
  max-width: 100%;
  min-width: 0;
  overflow: hidden;
}

.course-chapters-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 8px 10px;
  background: transparent;
  border: 0;
  cursor: pointer;
  font: inherit;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.course-chapters-toggle:hover {
  color: var(--ink);
}

.course-chapters-toggle small {
  margin-left: auto;
  font-weight: 600;
  color: var(--muted);
  font-size: 11px;
  text-transform: none;
  flex-shrink: 0;
}

.course-chapters-caret {
  display: inline-block;
  width: 10px;
  font-size: 9px;
  color: var(--muted);
  flex-shrink: 0;
}

.course-chapters-toggle > span:not(.course-chapters-caret) {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.course-chapters-list {
  list-style: none;
  padding: 0 0 6px;
  margin: 0;
  display: grid;
  gap: 1px;
  border-top: 1px solid var(--line);
}

.course-chapters-list li a {
  display: flex;
  gap: 8px;
  align-items: baseline;
  padding: 5px 12px;
  font-size: 12px;
  color: var(--muted);
  border-left: 2px solid transparent;
  min-width: 0;
  max-width: 100%;
}

.course-chapters-list li a:hover {
  background: var(--panel);
  color: var(--ink);
  border-left-color: var(--accent);
}

.course-chapters-list li.is-current a {
  background: var(--panel);
  color: var(--ink);
  border-left-color: var(--accent);
  font-weight: 700;
}

.course-chapter-num {
  font-weight: 700;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  min-width: 22px;
  flex-shrink: 0;
}

.course-chapter-name {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ----- Heading flash after navigating from a search result ----- */
.search-flash {
  animation: search-flash 1.6s ease-out;
}

@keyframes search-flash {
  0%   { background: rgba(59, 111, 91, 0.30); }
  60%  { background: rgba(59, 111, 91, 0.18); }
  100% { background: transparent; }
}

.chapter-hero .eyebrow a {
  color: var(--muted);
}

.chapter-hero .eyebrow a:hover {
  color: var(--ink);
}

.chapter-hero h1 {
  font-size: clamp(28px, 4vw, 48px);
  margin: 4px 0 12px;
}

.chapter-path {
  color: var(--muted);
  margin-top: -6px;
  margin-bottom: 12px;
  overflow-wrap: anywhere;
}

.chapter-path code {
  white-space: normal;
  overflow-wrap: anywhere;
}

.chapter-items-summary {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
  padding: 10px;
  background: var(--paper);
  border: 1px solid var(--line);
}

.hero-copy.error {
  color: var(--danger);
}

.chapter-body {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 30px 40px;
}

.chapter-listing ul.chapter-files {
  list-style: none;
  padding: 0;
  display: grid;
  gap: 6px;
}

.chapter-listing ul.chapter-files a {
  display: block;
  padding: 8px 12px;
  border: 1px solid var(--line);
  background: var(--paper);
}

.chapter-listing ul.chapter-files a:hover {
  border-color: var(--ink);
}

.mock-main .chapter-hero {
  margin-bottom: 14px;
}

/* ── Unified surface topbar ──────────────────────────────────────────────────
   Shared by course landing, chapter page, and mock-exam page. The hero block
   wraps a text column (eyebrow / H1 / subtitle), an optional meter, and a
   horizontal tab strip below them. */
.surface-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  grid-template-areas:
    "text meter"
    "tabs tabs";
  gap: 6px 24px;
  align-items: start;
}

.surface-hero .surface-hero-text { grid-area: text; min-width: 0; }
.surface-hero .hero-meter         { grid-area: meter; width: 160px; }
.surface-hero .surface-tabs       { grid-area: tabs; }
.surface-hero .surface-hero-text > *:last-child { margin-bottom: 0; }

/* Slim variant — used when the hero has no meter (e.g. course landing, where
   the mastery summary lives inside the heatmap section instead) */
.surface-hero-slim {
  grid-template-columns: minmax(0, 1fr);
  grid-template-areas: "text" "tabs";
  min-height: 0;
}

.surface-tabs {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  flex-wrap: wrap;
}

.surface-tab {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 8px 18px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  color: var(--muted);
  font-family: inherit;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  transition: background 0.1s, color 0.1s, border-color 0.1s;
}

.surface-tab:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.surface-tab.active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}

.surface-tabs-divider {
  width: 1px;
  align-self: stretch;
  background: var(--line);
  margin: 0 6px;
}

/* ── Mock Exams surface: exam selector + sub-tabs ───────────────────────────
   Compact pill-style chips for picking which paper to view. File-availability
   detail is in the tooltip; partial exams (missing paper OR solutions) render
   slightly dimmed. */
.exam-selector {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 12px 0 14px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.exam-chip {
  padding: 5px 14px;
  font-family: inherit;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.01em;
  background: var(--paper);
  border: 1px solid var(--line);
  color: var(--ink);
  cursor: pointer;
  border-radius: 999px;
  white-space: nowrap;
  transition: background 0.1s, color 0.1s, border-color 0.1s, opacity 0.1s;
}

.exam-chip:hover {
  border-color: var(--ink);
}

.exam-chip.active {
  background: var(--accent);
  color: var(--paper);
  border-color: var(--accent);
}

.exam-chip.partial:not(.active) {
  opacity: 0.55;
  font-style: italic;
}

.exam-chip:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.exam-subtabs {
  display: flex;
  gap: 2px;
  margin: 0 0 14px;
  border-bottom: 1px solid var(--line);
}

.exam-subtab {
  border: none;
  background: transparent;
  padding: 10px 18px;
  cursor: pointer;
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  color: var(--muted);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: color 0.1s, border-color 0.1s;
}

.exam-subtab:hover:not(.disabled):not([disabled]) {
  color: var(--ink);
}

.exam-subtab.active {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

.exam-subtab.disabled,
.exam-subtab[disabled] {
  opacity: 0.35;
  cursor: not-allowed;
}

/* ── Chapter prev/next navigation ───────────────────────────────────────────
   Two variants:
   - header — subtle text-only chips on the eyebrow line; reads as breadcrumb
   - footer — larger two-card row at the bottom of the article */

/* Tabs bar row — surface-tabs on the left, chapter prev/next chips on the right.
   Takes over the `tabs` grid area of the surface-hero so both sit on the same
   horizontal divider line. */
.chapter-hero-bar {
  grid-area: tabs;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  flex-wrap: wrap;
}
.chapter-hero-bar .surface-tabs {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

/* Header variant — minimal text chips, sits inline with the surface tabs */
.chapter-nav-header {
  display: flex;
  gap: 32px;
  flex-shrink: 0;
}
.chapter-nav-header .chapter-nav-link {
  display: flex;
  flex-direction: column;
  gap: 0;
  text-decoration: none;
  color: var(--muted);
  transition: color 0.1s;
}
.chapter-nav-header .chapter-nav-link.next { text-align: right; }
.chapter-nav-header .chapter-nav-link:hover { color: var(--ink); }
.chapter-nav-header .chapter-nav-link.disabled {
  opacity: 0.4;
  cursor: default;
  pointer-events: none;
}
.chapter-nav-header .chapter-nav-dir {
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  transition: color 0.1s;
}
.chapter-nav-header .chapter-nav-link:hover .chapter-nav-dir { color: var(--accent); }
.chapter-nav-header .chapter-nav-label {
  font-size: 12px;
  font-weight: 600;
  max-width: 180px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  border-bottom: 1px dashed transparent;
  transition: border-color 0.1s;
}
.chapter-nav-header .chapter-nav-link:hover .chapter-nav-label {
  border-bottom-color: var(--accent);
}

/* Footer variant — full-width two-card row at the bottom of the article */
.chapter-nav-footer {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin: 28px 0 8px;
}
.chapter-nav-footer .chapter-nav-link {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 10px 14px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  min-width: 0;
  transition: background 0.1s, color 0.1s, border-color 0.1s;
}
.chapter-nav-footer .chapter-nav-link.next { text-align: right; }
.chapter-nav-footer .chapter-nav-link:hover {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--paper);
}
.chapter-nav-footer .chapter-nav-link.disabled {
  opacity: 0.4;
  cursor: default;
  pointer-events: none;
}
.chapter-nav-footer .chapter-nav-dir {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}
.chapter-nav-footer .chapter-nav-link:hover .chapter-nav-dir { color: var(--paper); }
.chapter-nav-footer .chapter-nav-label {
  font-size: 16px;
  font-weight: 600;
  font-family: Georgia, Iowan Old Style, serif;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ── Chapter-local sub-tab strip ────────────────────────────────────────────
   Sits below the hero on chapter pages so Content / Self-Test reads as a
   distinct layer (this chapter's view), not as part of the course-level nav. */
.chapter-subtabs {
  display: flex;
  gap: 2px;
  margin: 0 0 18px;
  border-bottom: 1px solid var(--line);
}

.chapter-subtab {
  border: none;
  background: transparent;
  padding: 10px 18px;
  cursor: pointer;
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  color: var(--muted);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: color 0.1s, border-color 0.1s;
}

.chapter-subtab:hover {
  color: var(--ink);
}

.chapter-subtab.active {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

.practice-loader {
  margin-top: 20px;
  text-align: center;
  padding: 60px 30px;
  font-size: 15px;
  border: 1px dashed var(--line);
}

.practice-exam {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.practice-toolbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  background: var(--panel);
  border: 1px solid var(--line);
}

.practice-toolbar > small {
  flex: 1;
}

.practice-pager {
  display: flex;
  gap: 8px;
  align-items: center;
  padding: 10px 12px;
  background: var(--paper);
  border: 1px solid var(--line);
  flex-wrap: wrap;
}

.practice-pos {
  font-size: 14px;
  color: var(--ink);
  font-weight: 700;
  padding: 0 8px;
}

.practice-pos small {
  color: var(--muted);
  font-weight: 500;
}

/* No outer border around the group — the leaf parts render as their own cards.
   The wrapper is just a vertical-spacing container. */
.practice-group {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.practice-group-head {
  margin: 6px 0 4px;
}

.practice-group-head .eyebrow {
  margin: 0 0 2px;
}

.practice-group-head h2 {
  margin: 0;
  font-size: 22px;
  font-family: Georgia, Iowan Old Style, serif;
  font-weight: 700;
}

/* Practice progress heatmap inherits .q-progress base styling. */
.practice-progress {
  margin: 14px 0 16px;
}

/* ============================================================================
   Diagram kit — HTML diagrams styled with platform tokens.
   Used in knowledge-base markdown notes instead of Mermaid.
   ============================================================================ */
.diag {
  margin: 18px 0;
  padding: 14px 18px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  font-family: SFMono-Regular, Consolas, Liberation Mono, monospace;
  font-size: 12px;
  line-height: 1.4;
  color: var(--ink);
}

.diag-caption {
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  font-weight: 700;
  margin: 0 0 10px;
}

.diag-flow {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 10px;
}

.diag-stack {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 4px;
}

.diag-stack .diag-arrow { align-self: center; }

.diag-box {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 6px 10px;
  min-width: 60px;
  text-align: center;
  font-size: 12px;
}

.diag-box.accent  { border-color: var(--accent); background: rgba(59, 111, 91, 0.10); }
.diag-box.danger  { border-color: var(--danger); background: rgba(168, 79, 61, 0.10); }
.diag-box.secret  { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.diag-box.muted   { color: var(--muted); }
.diag-box.small   { padding: 4px 6px; font-size: 11px; min-width: 0; }
.diag-box.wide    { flex: 1; min-width: 0; }

.diag-arrow {
  color: var(--muted);
  font-weight: 700;
  user-select: none;
  white-space: nowrap;
}

.diag-arrow.accent { color: var(--accent); }

.diag-op {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  background: var(--panel);
  border: 1px solid var(--ink);
  border-radius: 50%;
  font-weight: 800;
  font-size: 11px;
  color: var(--ink);
}

.diag-label {
  color: var(--muted);
  font-size: 11px;
  align-self: center;
}

/* Sequence-style: 2 actors with messages between them */
.diag-seq {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 6px 12px;
  align-items: center;
}

.diag-seq-head { display: contents; }

.diag-seq-head > .actor {
  background: var(--ink);
  color: var(--paper);
  padding: 6px 10px;
  text-align: center;
  font-weight: 700;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  letter-spacing: 0.04em;
}

.diag-seq-head > .spacer { background: transparent; }

.diag-seq-msg { display: contents; }

.diag-seq-msg > .left,
.diag-seq-msg > .right {
  padding: 4px 6px;
  color: var(--muted);
  font-size: 11px;
}

.diag-seq-msg > .left { text-align: right; }

.diag-seq-msg > .arrow {
  color: var(--accent);
  font-weight: 700;
  text-align: center;
  white-space: nowrap;
}

.diag-seq-msg.note > .left,
.diag-seq-msg.note > .right { color: var(--ink); font-style: italic; }

/* Grid layout for parallel processes (block cipher modes etc.) */
.diag-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  gap: 10px;
  align-items: stretch;
}

.diag-grid-col {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 4px;
}

.diag-grid-col .diag-arrow,
.diag-grid-col .diag-op { align-self: center; }

/* A simple two-row layout — useful for "before/after" comparisons */
.diag-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.diag-compare > .side {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 10px 12px;
}

.diag-compare > .side strong {
  display: block;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin-bottom: 8px;
}

/* ============================================================================
   SVG diagram kit — inline SVG with real shapes / arrows / loops.
   Wrap each <svg> in <figure class="diag-figure"> with a <figcaption> for the
   title so the caption wraps via HTML (no in-SVG title that can collide with
   diagram elements).
   ============================================================================ */
.diag-figure {
  margin: 18px 0;
  padding: 0;
}

/* Figures attached to a practice-exam question (charts, diagrams, headlines
   cropped from the source paper). White matte so dark-on-transparent plots
   stay legible; bordered and centered like the chapter diagrams. */
.practice-figures {
  margin: 14px 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.practice-figure {
  display: block;
  max-width: 100%;
  width: auto;
  max-height: 420px;
  margin: 0 auto;
  background: #fff;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

/* Inline images embedded from a chapter folder via Obsidian's ![[file.png]]
   syntax. Sized to match the chapter's diagram figures so they don't blow up
   on wide screens. */
.md-embed-img {
  display: block;
  margin: 18px auto;
  max-width: 760px;
  width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

.diag-figure > figcaption {
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin-bottom: 6px;
}

svg.diag-svg {
  display: block;
  width: 100%;
  max-width: 760px;
  height: auto;
  margin: 0;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
}

/* In-SVG title class kept for legacy diagrams that still embed their title.
   Prefer the <figcaption> approach for new diagrams. */
svg.diag-svg .d-title {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  fill: var(--muted);
}

svg.diag-svg .d-h {
  font-family: Georgia, "Iowan Old Style", serif;
  font-size: 15px;
  font-weight: 700;
  fill: var(--ink);
}

svg.diag-svg .d-h-sm {
  font-family: Georgia, "Iowan Old Style", serif;
  font-size: 13px;
  font-weight: 700;
  fill: var(--ink);
}

svg.diag-svg .d-h-inv {
  font-family: Georgia, "Iowan Old Style", serif;
  font-size: 13px;
  font-weight: 700;
  fill: var(--paper);
}

svg.diag-svg .d-mono {
  font-family: SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 11px;
  fill: var(--ink);
}

svg.diag-svg .d-sub {
  font-family: SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 10px;
  fill: var(--muted);
}

svg.diag-svg .d-label {
  font-size: 10px;
  font-style: italic;
  fill: var(--muted);
}

svg.diag-svg .d-label-accent {
  font-size: 10px;
  font-weight: 700;
  fill: var(--accent);
}

svg.diag-svg .d-label-danger {
  font-size: 10px;
  font-weight: 700;
  fill: var(--danger);
}

svg.diag-svg .d-node      { fill: var(--panel); stroke: var(--line);   stroke-width: 1.5; }
svg.diag-svg .d-node-acc  { fill: rgba(59,111,91,0.10); stroke: var(--accent); stroke-width: 1.5; }
svg.diag-svg .d-node-dan  { fill: #fde9e3; stroke: var(--danger);   stroke-width: 1.5; }
svg.diag-svg .d-node-ink  { fill: var(--ink);   stroke: var(--ink);    stroke-width: 1.5; }
svg.diag-svg .d-edge      { stroke: var(--muted); stroke-width: 1.5; fill: none; }
svg.diag-svg .d-edge-acc  { stroke: var(--accent); stroke-width: 1.5; fill: none; }
svg.diag-svg .d-edge-dan  { stroke: var(--danger); stroke-width: 1.5; fill: none; }
svg.diag-svg .d-edge.dashed,
svg.diag-svg .d-edge-acc.dashed,
svg.diag-svg .d-edge-dan.dashed { stroke-dasharray: 5 4; }

/* Marker fill classes — used on the <path> inside <marker> elements. */
svg.diag-svg .d-arr     { fill: var(--muted); }
svg.diag-svg .d-arr-acc { fill: var(--accent); }
svg.diag-svg .d-arr-dan { fill: var(--danger); }

/* ============================================================================
   Step-through diagrams. Wrap a <figure class="diag-figure stepper" data-stepper>
   around an SVG whose elements carry `data-step="N"` (visible from step N
   onward) or `data-step-from="N" data-step-to="M"` (visible in [N, M]).
   A toolbar of prev/next + dot jumps gets wired up by bindSteppers() in app.js.
   ============================================================================ */
.diag-figure.stepper { display: block; }

.stepper-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 8px;
  font-size: 12px;
  color: var(--muted);
}

.stepper-bar button {
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  min-width: 34px;
  height: 30px;
  cursor: pointer;
  font: inherit;
  font-size: 11px;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 8px;
}

.stepper-bar button:hover:not(:disabled) {
  border-color: var(--ink);
}

.stepper-bar button:disabled {
  opacity: 0.3;
  cursor: default;
}

.stepper-bar button[data-step-goto].is-current {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}

.stepper-dots {
  display: inline-flex;
  gap: 4px;
}

.stepper-dots button {
  width: 26px;
  height: 26px;
  font-family: SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 11px;
}

.stepper-pos {
  font-family: SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 12px;
  margin-left: auto;
  color: var(--muted);
}

/* Element visibility states. Elements default to dim until revealed. */
.stepper svg.diag-svg [data-step],
.stepper svg.diag-svg [data-step-from] {
  opacity: 0.12;
  transition: opacity 0.2s ease;
}

.stepper:not(svg) [data-step],
.stepper:not(svg) [data-step-from] {
  display: none;
}

.stepper svg.diag-svg [data-step].is-revealed,
.stepper svg.diag-svg [data-step-from].is-revealed {
  opacity: 1;
}

.stepper:not(svg) [data-step].is-revealed,
.stepper:not(svg) [data-step-from].is-revealed {
  display: revert;
}

/* The element being introduced THIS step gets an outline highlight. */
.stepper svg.diag-svg [data-step].is-active,
.stepper svg.diag-svg [data-step-from].is-active {
  opacity: 1;
}

.stepper svg.diag-svg rect[data-step].is-active,
.stepper svg.diag-svg polygon[data-step].is-active,
.stepper svg.diag-svg circle[data-step].is-active {
  filter: drop-shadow(0 0 4px var(--accent));
}

.stepper svg.diag-svg line[data-step].is-active,
.stepper svg.diag-svg path[data-step].is-active {
  stroke-width: 2.5;
}

/* Step description text under the diagram — one visible at a time. */
.stepper-descs {
  margin: 10px 0 0;
}

.stepper-desc {
  display: none;
  margin: 0;
  padding: 10px 14px;
  background: var(--panel);
  border-left: 3px solid var(--accent);
  font-size: 13px;
  line-height: 1.5;
}

.stepper-desc.is-current {
  display: block;
}

.cipher-workthrough {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 0;
  margin: 18px 0;
}

.cipher-workthrough h3 {
  margin-bottom: 6px;
}

.cipher-workthrough .exam-note {
  color: var(--muted);
  font-size: 13px;
  margin-bottom: 14px;
}

.cipher-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 12px 0;
}

.cipher-card {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 12px;
}

.cipher-card strong {
  display: block;
  margin-bottom: 4px;
}

.cipher-card code {
  display: inline-block;
  margin-top: 4px;
}

.practical-workthrough {
  border-top: 3px solid var(--accent);
  box-shadow: 0 10px 24px rgba(22, 32, 25, 0.05);
}

.practical-head {
  padding: 16px 18px 14px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(117, 90, 155, 0.08), var(--paper));
}

.practical-head .eyebrow {
  margin-bottom: 8px;
  color: var(--accent);
}

.practical-head h3 {
  font-size: 22px;
  margin: 0 0 6px;
  line-height: 1.15;
}

.practical-head p:last-child {
  margin-bottom: 0;
}

.practical-stepper {
  margin: 0;
  padding: 0;
}

.practical-stepper figcaption {
  padding: 14px 18px 0;
  margin: 0;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  color: var(--muted);
  font-size: 13px;
}

.practical-stepper .stepper-bar {
  margin: 0;
  padding: 12px 18px 14px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
}

.practical-stepper .stepper-bar button {
  height: 28px;
  min-width: 30px;
  background: var(--panel);
}

.practical-stepper .stepper-dots {
  padding: 3px;
  gap: 3px;
  background: var(--paper);
  border: 1px solid var(--line);
}

.practical-stepper .stepper-dots button {
  border: 0;
  background: transparent;
}

.practical-stepper .stepper-dots button.is-current {
  background: var(--accent);
  color: var(--paper);
}

.practical-layout {
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  padding: 14px 18px 18px;
}

.practical-main {
  min-width: 0;
  overflow-x: auto;
}

.practical-steps {
  display: grid;
  gap: 6px;
}

.practical-steps > div {
  border: 1px solid var(--line);
  background: rgba(245, 243, 236, 0.7);
  padding: 8px 10px;
  opacity: 0.72;
}

.practical-steps > div.is-active {
  opacity: 1;
  background: rgba(117, 90, 155, 0.12);
  border-color: rgba(117, 90, 155, 0.42);
  box-shadow: inset 3px 0 0 var(--accent);
}

.practical-steps strong,
.practical-steps span {
  display: block;
}

.practical-steps span {
  color: var(--muted);
  font-size: 12px;
  margin-top: 2px;
}

.formula-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  border: 1px dashed var(--line);
  background: var(--paper);
  padding: 9px 10px;
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 13px;
}

.work-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--panel);
  margin: 0 0 10px;
  table-layout: fixed;
  min-width: 760px;
}

.work-table th,
.work-table td {
  border: 1px solid var(--line);
  padding: 9px 10px;
  text-align: center;
  vertical-align: middle;
}

.work-table th {
  background: var(--paper);
  text-align: left;
  font-weight: 700;
  width: 150px;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
}

.work-table td {
  font-family: SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}

.work-table thead th {
  text-align: center;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-size: 11px;
}

.work-table .answer-row th,
.work-table .answer-row td {
  background: rgba(117, 90, 155, 0.12);
  border-color: rgba(117, 90, 155, 0.35);
  font-weight: 800;
}

.work-table tr.is-active th,
.work-table tr.is-active td {
  outline: 2px solid rgba(117, 90, 155, 0.45);
  outline-offset: -2px;
  background: rgba(117, 90, 155, 0.08);
}

.compact-work-table {
  max-width: 620px;
}

.exam-answer,
.theory-box {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 11px 13px;
  margin: 8px 0 0;
}

.exam-answer {
  border-left: 3px solid var(--accent);
}

.exam-answer strong,
.theory-box strong {
  display: block;
  margin-bottom: 5px;
}

.theory-box {
  border-left: 3px solid var(--danger);
}

.practical-stepper .stepper-descs {
  padding: 0 18px 18px;
  margin: 0;
}

.practical-stepper .stepper-desc {
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  padding: 11px 13px;
}

.cipher-mode-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  padding: 16px 18px 18px;
}

.mode-card {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 14px;
}

.mode-card h4 {
  margin: 0 0 8px;
}

.mode-card ol {
  margin: 0;
  padding-left: 20px;
}

@media (max-width: 900px) {
  .practical-layout,
  .cipher-mode-grid {
    grid-template-columns: 1fr;
  }
}

.practice-progress .q-progress-cell {
  min-width: 28px;
  width: auto;
  padding: 0 6px;
  font-size: 10px;
}

/* Practice parts render with the chapter self-test .question-card shell, which
   already provides border + padding + background. We just add list-style reset
   (it's a <li>) and a small gap between cards. */
.practice-part {
  list-style: none;
  margin-top: 12px;
}

.practice-part:first-of-type { margin-top: 0; }

.practice-part-head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.practice-part-label {
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 22px;
  font-weight: 700;
  color: var(--ink);
  min-width: 60px;
}

.marks-badge-sm {
  font-size: 11px;
  padding: 2px 7px;
}

.marks-badge {
  display: inline-block;
  background: var(--ink);
  color: var(--paper);
  padding: 3px 10px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.practice-score {
  margin-left: auto;
  font-size: 14px;
  color: var(--muted);
}

.practice-score strong {
  color: var(--ink);
  font-size: 16px;
}

.practice-q-body {
  font-size: 16px;
  line-height: 1.55;
  margin-bottom: 18px;
  padding: 14px 16px;
  background: var(--paper);
  border-left: 3px solid var(--line);
}

.practice-q-body.markdown-body {
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 16px;
  max-width: none;
}

.practice-q-body p {
  margin: 0 0 0.6em;
}

.practice-q-body p:last-child { margin: 0; }

.practice-shared-context {
  margin: 0 0 22px;
  padding: 18px 22px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
}

.practice-shared-context h4 {
  margin: 0 0 10px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.practice-shared-context .markdown-body {
  font-size: 15px;
  max-width: none;
}

.practice-shared-context .markdown-body p {
  margin: 0 0 0.7em;
}

.practice-shared-context .markdown-body p:last-child {
  margin: 0;
}

/* Old .practice-toggle / .practice-guidance / .practice-answer / .practice-grade /
   .practice-attempt rules removed — the practice exam now reuses the chapter
   self-test card structure (.question-card + .q-grade + .q-expected). */

.practice-footer {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 12px 14px;
  background: var(--paper);
  border: 1px solid var(--line);
  flex-wrap: wrap;
}

.pdf-viewer {
  background: var(--panel);
  border: 1px solid var(--line);
  height: calc(100vh - 220px);
  overflow: hidden;
}

.pdf-viewer iframe {
  width: 100%;
  height: 100%;
  border: 0;
  display: block;
}

.pdf-outline {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 2px;
}

.pdf-outline li a {
  display: block;
  padding: 4px 6px;
  border-left: 2px solid transparent;
  color: var(--ink);
  font-size: 13px;
}

.pdf-outline li.lvl-1 a { padding-left: 18px; color: var(--muted); }
.pdf-outline li.lvl-2 a { padding-left: 28px; color: var(--muted); font-size: 12px; }
.pdf-outline li.lvl-3 a { padding-left: 36px; color: var(--muted); font-size: 12px; }

.pdf-outline li a:hover {
  border-left-color: var(--accent);
  background: var(--paper);
}

.pdf-outline li a small {
  color: var(--muted);
  margin-left: 4px;
}

/* TOC chapter row with both filter (click name) + open-chapter (click Open) */
.pdf-outline li.toc-chapter-row {
  display: flex;
  align-items: stretch;
}

.pdf-outline li.toc-chapter-row .toc-chapter-filter {
  flex: 1;
  min-width: 0;
}

.pdf-outline li.toc-chapter-row .toc-open-chapter {
  flex-shrink: 0;
  padding: 4px 10px;
  font-size: 11px;
  color: var(--muted);
  text-decoration: none;
  border-left: 1px dashed var(--line);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.pdf-outline li.toc-chapter-row .toc-open-chapter:hover {
  background: var(--paper);
  color: var(--ink);
}

/* Mock-question card "Ch X · topic" badge becomes a real link to the chapter */
.q-source.q-source-link {
  color: var(--accent);
  text-decoration: none;
  cursor: pointer;
  border-bottom: 1px dashed transparent;
  transition: border-color 0.1s;
}

.q-source.q-source-link:hover {
  border-bottom-color: var(--accent);
}

.pdf-outline li.kind-question > a,
.pdf-outline li.kind-section > a {
  font-weight: 700;
  color: var(--ink);
}

.pdf-outline li.kind-subquestion > a {
  color: var(--muted);
  font-size: 12px;
}

.pdf-outline.mq-toc li.active > a {
  border-left-color: var(--accent);
  background: var(--paper);
  color: var(--ink);
  font-weight: 700;
}

.mq-panel {
  padding: 0;
}

.mq-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  padding: 14px 0 12px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 14px;
  flex-wrap: wrap;
}

.mq-head h2 {
  margin: 4px 0 6px;
  font-size: 22px;
  font-family: Georgia, Iowan Old Style, serif;
}

.mq-head .q-toolbar {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  align-items: center;
}

.mq-mix {
  margin: 0;
  font-style: italic;
  max-width: 520px;
}

.mq-intro {
  padding: 30px;
  border: 1px dashed var(--line);
  background: var(--panel);
  max-width: 720px;
  margin: 20px auto;
  text-align: center;
}

.mq-intro h2 {
  margin: 0 0 8px;
  font-family: Georgia, Iowan Old Style, serif;
}

.mq-intro p {
  color: var(--muted);
  margin-bottom: 16px;
}

.mq-intro .error {
  color: var(--danger);
}

/* ----- Course landing layout (2-column on wide screens) ----- */
.course-layout {
  display: grid;
  grid-template-columns: minmax(240px, 300px) minmax(0, 1fr);
  gap: 20px;
  align-items: start;
  margin-bottom: 32px;
}

.course-home-grid {
  grid-template-columns: minmax(320px, var(--toc-width, 320px)) 6px minmax(0, 1fr);
}

:root[data-toc-collapsed="true"] .course-home-grid {
  grid-template-columns: 36px 0 minmax(0, 1fr);
}

.course-home-main {
  padding-bottom: 48px;
  min-width: 0;
}

.chapter-toc.course-toc {
  position: relative;
  height: 100%;
  min-height: 0;
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 14px 14px 18px;
  overflow: hidden;
}

:root[data-toc-collapsed="true"] .chapter-toc.course-toc {
  align-self: start;
  height: auto;
  min-height: 0;
  padding: 0;
  border: 0;
  background: transparent;
}

.chapter-toc.course-toc > .rail-collapsible {
  padding: 18px 0 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
  height: 100%;
  min-height: 0;
  overflow: hidden;
  padding-right: 0;
}

.chapter-toc.course-toc h4 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0;
}

.course-nav-search {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 0 10px;
  height: 32px;
  flex-shrink: 0;
}

.course-nav-search:focus-within {
  border-color: var(--accent);
}

.course-nav-icon {
  font-size: 12px;
  color: var(--muted);
  flex-shrink: 0;
}

.course-nav-input {
  flex: 1;
  border: 0;
  outline: 0;
  background: transparent;
  height: 100%;
  font-size: 12px;
  color: var(--ink);
}

.course-nav-input::placeholder { color: var(--muted); }

.course-nav-clear {
  border: 0;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 16px;
  line-height: 1;
  padding: 0 2px;
}

.course-nav-clear:hover { color: var(--ink); }

.course-nav-scroll {
  flex: 1 1 auto;
  min-height: 0;
  overflow-x: hidden;
  overflow-y: auto;
  padding-right: 4px;
  scrollbar-gutter: stable;
}

.course-nav-scroll .course-chapters-section:last-child {
  margin-bottom: 0;
}

/* The chapter list inherits .course-chapters-list styling. We refine spacing for
   the per-chapter row (3-column grid: num · name · pct) so it stays compact. */
.course-chapters-section .course-chapters-toggle.as-heading {
  cursor: default;
}

.course-toc .course-chapters-section {
  min-width: 0;
  overflow: hidden;
}

.course-nav-chapter-row {
  display: block;
}

.course-nav-chapter-btn,
.course-nav-chapter-row > a,
.course-chapters-list.course-nav-chapters > li > a {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  gap: 10px;
  align-items: baseline;
  width: 100%;
  padding: 9px 12px;
  color: var(--muted);
  border-left: 2px solid transparent;
  border-top: 0;
  border-right: 0;
  border-bottom: 0;
  background: transparent;
  font-size: 12px;
  text-align: left;
  cursor: pointer;
}

.course-nav-chapter-btn:hover,
.course-nav-chapter-row > a:hover,
.course-chapters-list.course-nav-chapters > li > a:hover {
  background: var(--panel);
  color: var(--ink);
  border-left-color: var(--accent);
}

.course-chapters-list.course-nav-chapters > li.is-read .course-nav-chapter-btn,
.course-chapters-list.course-nav-chapters > li.is-read .course-nav-chapter-row > a,
.course-chapters-list.course-nav-chapters > li.is-read > a {
  border-left-color: var(--accent);
  color: var(--ink);
}

.course-chapters-list.course-nav-chapters .course-chapter-name {
  font-weight: 600;
  color: var(--ink);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.course-chapters-list.course-nav-chapters .course-nav-pct {
  font-variant-numeric: tabular-nums;
  font-size: 11px;
  color: var(--muted);
  font-weight: 700;
}

/* Nested chapter headings inside the home TOC */
.course-nav-topics {
  list-style: none;
  padding: 3px 0 10px 42px;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0;
  border-top: 1px dashed var(--line);
}

.course-nav-topic-link {
  display: flex;
  align-items: center;
  width: 100%;
  min-height: 26px;
  padding: 4px 8px;
  font: inherit;
  font-size: 11px;
  line-height: 1.25;
  color: var(--muted);
  border-left: 2px solid transparent;
}

.course-nav-topic-link:hover {
  background: var(--paper);
  border-left-color: var(--accent);
  color: var(--ink);
}

.course-nav-topic-link span {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.course-nav-topic.lvl-2 .course-nav-topic-link {
  color: var(--ink);
  font-weight: 600;
}

.course-nav-topic.lvl-3 .course-nav-topic-link {
  padding-left: 16px;
  font-size: 10.5px;
}

.course-main-col {
  min-width: 0;
}

.course-toolkit-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 16px 18px;
  margin: 16px 0;
}

.toolkit-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.toolkit-tab {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 8px;
  min-width: 210px;
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 9px 10px;
}

.toolkit-tab:hover {
  border-color: var(--accent);
  background: var(--panel);
}

.toolkit-tab span,
.toolkit-tab em {
  color: var(--muted);
  font-size: 12px;
  font-style: normal;
  font-weight: 700;
}

.toolkit-tab strong {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* On narrow screens, drop the sidebar above the cards */
@media (max-width: 1100px) {
  .course-layout {
    grid-template-columns: 1fr;
  }
  .course-home-grid {
    grid-template-columns: 1fr;
    overflow-y: auto;
  }
  :root[data-toc-collapsed="true"] .course-home-grid {
    grid-template-columns: 1fr;
  }
  .course-home-grid > .resize-handle {
    display: none;
  }
  .chapter-toc.course-toc {
    position: static;
    height: auto;
  }
  .course-home-main {
    height: auto;
    overflow: visible;
  }
}

/* ----- Self-update banner (dashboard) ------------------------------------- */
.update-banner {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 16px;
  padding: 14px 18px;
  margin: 0 0 20px;
  background: #fff8e6;
  border: 1px solid #e6c97a;
  border-left: 4px solid #c08a3e;
}
.update-banner.pulling { background: #eef4f0; border-color: #b2cabd; border-left-color: #5a8a5a; }
.update-banner.done    { background: #e8f1ea; border-color: #a8c8b2; border-left-color: #5a8a5a; }
.update-banner.error   { background: #fbeae6; border-color: #e3b5ab; border-left-color: #b66355; }
.update-banner-icon {
  font-size: 24px;
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  background: var(--paper);
  font-weight: 800;
  color: var(--ink);
}
.update-banner.pulling .update-banner-icon { animation: spin 1.4s linear infinite; }
@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }
.update-banner-body h3 {
  margin: 2px 0 4px;
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 18px;
}
.update-banner-body small code {
  background: rgba(0,0,0,0.05);
  padding: 1px 5px;
}
.update-banner-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ----- Code editor (CodeMirror) attempt boxes ----------------------------- */
.code-attempt {
  display: flex;
  flex-direction: column;
  gap: 0;
}
.code-editor-toolbar {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  padding: 4px 8px;
  background: var(--panel-2, #ebe7dc);
  border: 1px solid var(--line);
  border-bottom: none;
  font-size: 11px;
}
.code-lang-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--muted);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.code-lang-select {
  font: inherit;
  font-size: 11px;
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 2px 6px;
}
.code-attempt .CodeMirror {
  font-family: ui-monospace, SF Mono, Menlo, Monaco, Consolas, monospace;
  font-size: 13px;
  line-height: 1.5;
  border: 1px solid var(--line);
  min-height: 160px;
  background: var(--paper);
}
.code-attempt .CodeMirror-gutters {
  background: var(--panel-2, #ebe7dc);
  border-right: 1px solid var(--line);
}
.code-attempt .CodeMirror-linenumber {
  color: var(--muted);
  font-size: 11px;
}
.code-attempt .CodeMirror-cursor { border-left-color: var(--accent); }
/* keep image upload affordance flush */
.code-attempt .image-thumbs,
.code-attempt .attempt-drop-hint {
  margin-top: 4px;
}

/* ----- "Clear progress" affordances ---------------------------------------- */
.hero-actions-row {
  margin-top: 10px;
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
}
.clear-link {
  background: transparent;
  border: 1px solid transparent;
  color: var(--muted);
  font: inherit;
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-weight: 700;
  padding: 3px 8px;
  cursor: pointer;
  transition: color 0.1s, border-color 0.1s, background 0.1s;
}
.clear-link:hover {
  color: #b66355;
  border-color: rgba(182, 99, 85, 0.4);
  background: rgba(182, 99, 85, 0.06);
}
/* When used inline next to other toolbar buttons (.tb-btn .clear-link) — keep
   the danger styling but match the toolbar baseline */
.tb-btn.clear-link {
  border: 1px solid var(--line);
}
.tb-btn.clear-link:hover {
  border-color: #b66355;
  color: #b66355;
}
/* On per-question cards — same .btn baseline, danger-on-hover */
.btn.clear-link {
  color: var(--muted);
}
.btn.clear-link:hover {
  color: #b66355;
  border-color: rgba(182, 99, 85, 0.5);
}

/* Tiny "×" on each chapter heatmap tile, only visible on tile hover */
.spine-tile { position: relative; }
.spine-tile-clear {
  position: absolute;
  top: 4px;
  right: 4px;
  width: 16px;
  height: 16px;
  padding: 0;
  border: 1px solid transparent;
  background: transparent;
  color: rgba(0,0,0,0.35);
  font: 700 12px/14px var(--font, sans-serif);
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.1s, color 0.1s, border-color 0.1s, background 0.1s;
}
.spine-tile:hover .spine-tile-clear {
  opacity: 1;
}
.spine-tile-clear:hover {
  color: #b66355;
  border-color: rgba(182, 99, 85, 0.5);
  background: rgba(255,255,255,0.7);
}

/* ----- "Contents populated" chip in the course hero ----------------------- */
.course-populated-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 14px;
  padding: 4px 10px 4px 8px;
  background: var(--paper);
  border: 1px solid var(--line);
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 700;
}
.course-populated-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #5a8a5a;
  font-size: 0;
  line-height: 0;
}
.course-populated-label { color: var(--ink); }
.course-populated-rerun {
  border: none;
  background: transparent;
  padding: 2px 4px 2px 8px;
  margin-left: 4px;
  font: inherit;
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  cursor: pointer;
  border-left: 1px solid var(--line);
  transition: color 0.1s;
}
.course-populated-rerun:hover { color: var(--accent); }

/* ----- Generate-all card on course landing -------------------------------- */
.genall-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent);
  padding: 16px 20px;
  margin: 18px 0 0;
  box-shadow: var(--shadow);
}
.genall-card.live   { border-top-color: var(--accent); }
.genall-card.finished { border-top-color: #6b8e6b; }
.genall-card.failed { border-top-color: #b66355; }

.genall-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
}
.genall-head h3 {
  margin: 4px 0 6px;
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 22px;
  line-height: 1.15;
}

.genall-bar {
  height: 4px;
  background: var(--line);
  margin: 12px 0;
  overflow: hidden;
}
.genall-bar-fill {
  height: 100%;
  background: var(--accent);
  transition: width 0.3s ease;
}

.genall-steps {
  font-size: 12px;
  color: var(--muted);
}
.genall-steps summary {
  cursor: pointer;
  padding: 4px 0;
}
.genall-steps ul {
  list-style: none;
  padding: 0;
  margin: 8px 0 0;
  border-top: 1px solid var(--line);
}
.genall-step {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 5px 0;
  border-bottom: 1px dashed var(--line);
}
.genall-step-status {
  display: inline-block;
  width: 18px;
  text-align: center;
  font-weight: 700;
}
.genall-step-done    .genall-step-status { color: #5a8a5a; }
.genall-step-skipped .genall-step-status { color: var(--muted); opacity: 0.6; }
.genall-step-running .genall-step-status { color: var(--accent); }
.genall-step-error   .genall-step-status { color: #b66355; }
.genall-step-pending .genall-step-status { color: var(--muted); opacity: 0.4; }
.genall-step-label { flex: 1; min-width: 0; color: var(--ink); }
.genall-step-skipped .genall-step-label { color: var(--muted); }
.genall-step-error .genall-step-error {
  display: block;
  margin-top: 2px;
  color: #b66355;
  font-style: italic;
  width: 100%;
}

/* ----- Master generate-all-courses card (dashboard footer) ---------------- */
.genall-all-card {
  margin-top: 28px;
}
.genall-master-list {
  list-style: none;
  padding: 0;
  margin: 12px 0 0;
}
.genall-master-row {
  display: grid;
  grid-template-columns: 24px minmax(80px, auto) 1fr auto;
  align-items: center;
  gap: 12px;
  padding: 8px 0;
  border-bottom: 1px dashed var(--line);
}
.genall-master-status {
  text-align: center;
  font-weight: 800;
  font-size: 14px;
}
.genall-master-pending .genall-master-status { color: var(--muted); opacity: 0.5; }
.genall-master-running .genall-master-status { color: var(--accent); }
.genall-master-done    .genall-master-status { color: #5a8a5a; }
.genall-master-error   .genall-master-status { color: #b66355; }
.genall-master-course {
  font-weight: 700;
  font-family: Georgia, Iowan Old Style, serif;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-size: 14px;
}
.genall-master-pending .genall-master-course { color: var(--muted); }
.genall-master-progress {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}
.genall-master-bar {
  flex: 1;
  height: 4px;
  background: var(--line);
  overflow: hidden;
  max-width: 280px;
  min-width: 80px;
}
.genall-master-bar-fill {
  display: block;
  height: 100%;
  background: var(--accent);
  transition: width 0.3s ease;
}
.genall-master-progress small { color: var(--muted); font-size: 11px; white-space: nowrap; }
.genall-master-running-label {
  grid-column: 1 / -1;
  color: var(--muted);
  font-size: 11px;
  padding-left: 36px;
  font-style: italic;
  margin-top: -4px;
}

/* ----- Chapter progress (course landing) — card grid + spine ----- */
.course-spine-section {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent);
  padding: 18px 22px;
  margin: 24px 0 16px;
  box-shadow: var(--shadow);
}

.course-spine-section .panel-head {
  margin-bottom: 12px;
}

/* Panel head — heatmap variant puts the course-wide summary on the right */
.spine-head { align-items: flex-start; }
.spine-summary {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 2px;
  text-align: right;
}
.spine-summary-pct {
  font-family: Georgia, Iowan Old Style, serif;
  font-weight: 800;
  font-size: 32px;
  line-height: 1;
  color: var(--ink);
}
.spine-summary small { color: var(--muted); font-size: 12px; }

/* Signal legend — one row above the grid, low-key */
.spine-legend {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  font-size: 11px;
  color: var(--muted);
  margin: 0 0 10px;
  padding: 6px 10px;
  background: var(--paper);
  border: 1px solid var(--line);
}
.spine-legend-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.spine-legend-pip {
  display: inline-block;
  width: 14px;
  height: 4px;
  background: var(--c, var(--accent));
  border-radius: 1px;
}
.spine-legend-note { margin-left: auto; font-style: italic; }

.course-spine {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 8px;
}

.spine-tile {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 10px 12px;
  background: var(--paper);
  border: 1px solid var(--line);
  color: var(--ink);
  font-size: 12px;
  text-decoration: none;
  transition: transform 0.08s, box-shadow 0.08s;
}

.spine-tile:hover { transform: translateY(-1px); box-shadow: 0 4px 10px rgba(22,32,25,0.12); }

.spine-tile-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

.spine-num {
  font-family: Georgia, Iowan Old Style, serif;
  font-weight: 700;
  font-size: 18px;
  line-height: 1;
}

.spine-pct {
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: 13px;
}

.spine-name {
  font-size: 11px;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.25;
}

.spine-bars {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 3px;
  margin-top: 2px;
}

.spine-bar {
  height: 4px;
  background: rgba(22, 32, 25, 0.10);
  position: relative;
  overflow: hidden;
  border-radius: 1px;
}

.spine-bar::after {
  content: '';
  position: absolute;
  inset: 0;
  width: var(--fill, 0%);
  background: var(--bar-color, var(--accent));
  transition: width 0.2s;
}

.spine-bar-read     { --bar-color: #3b6f5b; }
.spine-bar-practice { --bar-color: #5b8aa3; }
.spine-bar-mock     { --bar-color: #c08a3e; }
.spine-bar-fc       { --bar-color: #9a6fa0; }

/* Mastery bucket tint (background only — bars retain their own colour) */
.spine-none  { background: var(--paper); }
.spine-low   { background: #fde9e3; border-color: #f0c8c0; }
.spine-mid   { background: #fcefce; border-color: #f3e2c8; }
.spine-good  { background: #dfecd9; border-color: #c5dab8; }
.spine-great { background: #cfe2d6; border-color: #afcfba; }
.spine-great .spine-bar { background: rgba(22, 32, 25, 0.18); }

.chapter-progress-grid {
  display: grid;
  gap: 10px;
}

.chapter-progress-grid .panel-head {
  margin: 8px 0 6px;
}

/* Compact single-row chapter card with collapsible topics underneath */
.ch-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid transparent;
  transition: border-color 0.12s, box-shadow 0.12s;
}

.ch-card.is-read {
  border-left-color: var(--accent);
}

.ch-card:hover {
  box-shadow: 0 2px 8px rgba(22, 32, 25, 0.06);
}

.ch-card-row {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 14px;
  min-height: 48px;
}

.ch-card-title {
  flex: 1 1 auto;
  display: flex;
  align-items: baseline;
  gap: 8px;
  color: var(--ink);
  min-width: 0;
  overflow: hidden;
}

.ch-card-num {
  font-family: Georgia, Iowan Old Style, serif;
  font-weight: 700;
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
  letter-spacing: 0.04em;
}

.ch-card-num::before { content: 'Ch '; }

.ch-card-title h3 {
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.2;
  margin: 0;
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.ch-card-badge {
  font-size: 10px;
  font-weight: 800;
  color: var(--accent);
  border: 1px solid var(--accent);
  width: 18px;
  height: 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  line-height: 1;
}

.ch-card-metrics {
  display: flex;
  gap: 14px;
  align-items: center;
  flex-shrink: 0;
}

.ch-card-metric {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  color: var(--muted);
}

.ch-card-metric-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.ch-card-metric-text small {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  font-weight: 700;
}

.ch-card-metric-text em {
  font-style: normal;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  font-size: 11px;
}

.ch-card-overall {
  flex-shrink: 0;
  min-width: 44px;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.ch-card-overall strong {
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1;
}

.ch-card-expand {
  border: 1px solid var(--line);
  background: var(--paper);
  width: 26px;
  height: 26px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  color: var(--muted);
  cursor: pointer;
  padding: 0;
  flex-shrink: 0;
}

.ch-card-expand:hover {
  color: var(--ink);
  border-color: var(--ink);
}

@media (max-width: 1280px) {
  .ch-card-metric-text small { display: none; }
}

@media (max-width: 1000px) {
  .ch-card-row {
    flex-wrap: wrap;
    gap: 8px 12px;
  }
  .ch-card-title { flex-basis: 100%; }
  .ch-card-metrics { gap: 10px; }
}

/* SVG ring */
.ring {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.ring-text {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 10px;
  font-weight: 700;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  font-family: SFMono-Regular, Consolas, monospace;
}

/* Chapter outline inside the expanded chapter card */
.ch-card-topics {
  padding: 0;
  border-top: 1px dashed var(--line);
  background: var(--paper);
}

.ch-card-topics .eyebrow {
  margin: 0 0 8px;
}

.chapter-heading-outline {
  display: grid;
  gap: 0;
}

.chapter-heading-group {
  min-width: 0;
  display: grid;
  grid-template-columns: minmax(220px, 0.85fr) minmax(0, 1.6fr);
  gap: 14px;
  align-items: start;
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
}

.chapter-heading-group:last-child {
  border-bottom: 0;
}

.chapter-heading-main,
.chapter-heading-sub {
  display: block;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.chapter-heading-main {
  color: var(--ink);
  font-size: 12px;
  font-weight: 800;
  line-height: 1.35;
  white-space: normal;
}

.chapter-heading-main:hover,
.chapter-heading-sub:hover {
  color: var(--accent);
}

.chapter-heading-subgrid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 6px 16px;
  margin-top: 1px;
}

.chapter-heading-sub {
  color: var(--muted);
  font-size: 11px;
  line-height: 1.35;
  padding-left: 10px;
  border-left: 2px solid var(--line);
}

.chapter-heading-sub:hover {
  border-left-color: var(--accent);
}

.topic-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.topic-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 6px 10px;
  cursor: pointer;
  font: inherit;
  font-size: 12px;
  color: var(--ink);
  transition: border-color 0.1s, background 0.1s;
}

.topic-chip:hover {
  border-color: var(--ink);
}

.topic-chip.lvl-0 { color: var(--muted); }
.topic-chip.lvl-1 { border-left: 3px solid #c5dab8; }
.topic-chip.lvl-2 { border-left: 3px solid #8aae7f; }
.topic-chip.lvl-3 { border-left: 3px solid #3b6f5b; }
.topic-chip.lvl-4 { background: var(--accent); border-color: var(--accent); color: var(--paper); }

.topic-chip.heading-chip {
  text-decoration: none;
  border-left: 3px solid var(--accent);
}

.topic-chip.heading-chip.lvl-3 {
  border-left-color: var(--line-strong);
  color: var(--muted);
}

.topic-chip-title {
  font-weight: 600;
}

.topic-dots {
  font-size: 9px;
  letter-spacing: 1px;
  color: var(--accent);
  flex-shrink: 0;
}

.topic-chip.lvl-4 .topic-dots {
  color: var(--paper);
}

.topic-chip.lvl-0 .topic-dots {
  color: var(--muted);
}

.topic-empty {
  color: var(--muted);
  font-style: italic;
  font-size: 12px;
}

/* Chapter progress card in the rail */
.chapter-progress-card .cp-dial {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  margin-bottom: 10px;
}

.chapter-progress-card .cp-dial strong {
  font-size: 28px;
  font-family: Georgia, Iowan Old Style, serif;
  line-height: 1;
  color: var(--ink);
}

.chapter-progress-card .cp-dial .mini-bar {
  width: 100%;
  height: 6px;
  background: var(--paper);
  border: 1px solid var(--line);
}

.chapter-progress-card .cp-dial small {
  color: var(--muted);
  font-size: 11px;
}

.cp-rows {
  display: grid;
  gap: 6px;
  margin-bottom: 12px;
}

.cp-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4px 10px;
  padding: 5px 0;
  border-bottom: 1px dashed var(--line);
  font-size: 12px;
}

.cp-row:last-child { border-bottom: 0; }

.cp-row-label { color: var(--muted); }
.cp-row-value { font-weight: 700; color: var(--ink); }
.cp-row-sub {
  grid-column: 1 / -1;
  color: var(--muted);
  font-style: italic;
  font-size: 10px;
}

.cp-read-toggle {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 8px 12px;
  cursor: pointer;
  font: inherit;
  font-size: 12px;
  color: var(--muted);
}

.cp-read-toggle:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.cp-read-toggle.is-read {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}

.chapter-read-footer {
  margin-top: 32px;
  padding: 20px;
  background: var(--paper);
  border: 1px dashed var(--line);
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
}

.chapter-read-footer .cp-read-toggle {
  max-width: 400px;
}

/* ----- Flashcards (mock-exam tab) ----- */
.fc-panel { padding: 0; }

.fc-head .fc-mix {
  max-width: 720px;
  font-style: italic;
}

.fc-global-actions {
  flex-wrap: wrap;
}

/* ----- Background jobs banner ----- */
.bg-jobs {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 250;
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 360px;
  pointer-events: none;
}

.bg-job {
  pointer-events: auto;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 12px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
  box-shadow: 0 12px 32px rgba(22, 32, 25, 0.22);
  font-size: 13px;
  line-height: 1.4;
}

.bg-job-done { border-left-color: #16a34a; }
.bg-job-error { border-left-color: var(--danger); }

.bg-job-icon {
  flex-shrink: 0;
  font-size: 14px;
  width: 22px;
  height: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
}

.bg-job-done .bg-job-icon { color: #16a34a; }
.bg-job-error .bg-job-icon { color: var(--danger); }

.bg-job-spinner {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid var(--line);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: bg-job-spin 0.9s linear infinite;
}

@keyframes bg-job-spin {
  to { transform: rotate(360deg); }
}

.bg-job-body {
  flex: 1;
  min-width: 0;
}

.bg-job-body strong {
  display: block;
  font-weight: 700;
  color: var(--ink);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.bg-job-body small {
  color: var(--muted);
  font-size: 11px;
}

.bg-job-dismiss {
  flex-shrink: 0;
  border: 0;
  background: transparent;
  color: var(--muted);
  font-size: 16px;
  line-height: 1;
  cursor: pointer;
  padding: 2px 4px;
}

.bg-job-dismiss:hover { color: var(--ink); }

.fc-chapter {
  border: 1px solid var(--line);
  background: var(--panel);
  margin-bottom: 12px;
}

.fc-chapter-head {
  display: flex;
  gap: 10px;
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  flex-wrap: wrap;
}

.fc-chapter-toggle {
  flex: 1 1 auto;
  display: flex;
  gap: 8px;
  align-items: baseline;
  background: transparent;
  border: 0;
  padding: 0;
  font: inherit;
  cursor: pointer;
  color: var(--ink);
  text-align: left;
  min-width: 0;
}

.fc-chapter-toggle strong { font-weight: 700; }
.fc-chapter-toggle small {
  color: var(--muted);
  font-size: 12px;
}

.fc-caret {
  display: inline-block;
  width: 12px;
  color: var(--muted);
}

.fc-chapter-actions {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.fc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 10px;
  padding: 14px;
}

.fc-empty {
  padding: 24px 16px;
  color: var(--muted);
  font-style: italic;
}

.fc-card {
  border: 1px solid var(--line);
  background: var(--paper);
  display: flex;
  flex-direction: column;
  min-height: 140px;
  position: relative;
}

.fc-card.is-ai {
  border-top: 3px solid var(--accent);
}

.fc-card.is-custom {
  border-top: 3px solid #8a8278;
}

.fc-card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  border-bottom: 1px solid var(--line);
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.fc-card-source {
  font-weight: 700;
}

.fc-card-due {
  color: var(--accent);
  font-weight: 700;
}

.fc-card-next {
  color: var(--muted);
  text-transform: none;
  letter-spacing: 0;
  font-size: 11px;
}

.fc-card-actions {
  margin-left: auto;
  display: flex;
  gap: 4px;
}

.fc-icon-btn {
  border: 1px solid transparent;
  background: transparent;
  width: 22px;
  height: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  color: var(--muted);
  cursor: pointer;
  padding: 0;
}

.fc-icon-btn:hover {
  color: var(--ink);
  border-color: var(--line);
  background: var(--panel);
}

.fc-icon-btn.fc-icon-danger:hover {
  color: var(--danger);
  border-color: var(--danger);
}

.fc-card-body {
  flex: 1;
  border: 0;
  background: transparent;
  padding: 14px;
  font: inherit;
  font-size: 14px;
  line-height: 1.45;
  cursor: pointer;
  text-align: left;
  color: var(--ink);
  position: relative;
  min-height: 90px;
}

.fc-card-side {
  display: none;
}

.fc-card-side.fc-card-front {
  display: block;
}

.fc-card.is-flipped .fc-card-side.fc-card-front {
  display: none;
}

.fc-card.is-flipped .fc-card-side.fc-card-back {
  display: block;
  font-size: 13px;
  color: var(--muted);
}

.fc-card-body:hover {
  background: rgba(59, 111, 91, 0.05);
}

.fc-form {
  padding: 14px;
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.fc-form label {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.fc-form-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  font-weight: 700;
}

.fc-form textarea {
  border: 1px solid var(--line);
  padding: 8px 10px;
  font: inherit;
  font-size: 13px;
  resize: vertical;
}

.fc-form textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.fc-form-actions {
  display: flex;
  gap: 6px;
}

.fc-card-edit {
  grid-column: 1 / -1;
}

/* AI generate modal */
.fc-gen-prompt {
  width: 100%;
  min-height: 80px;
  border: 1px solid var(--line);
  padding: 8px 10px;
  font: inherit;
  font-size: 13px;
  resize: vertical;
  margin-bottom: 4px;
}

/* Study modal */
.fc-study {
  max-width: 640px;
  width: 100%;
}

.fc-study-card {
  padding: 28px 24px;
  min-height: 220px;
  background: var(--paper);
  border: 1px solid var(--line);
  margin: 16px 0;
  font-size: 16px;
  line-height: 1.55;
}

.fc-study-front {
  font-weight: 600;
}

.fc-recall-box {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.fc-recall-box label {
  display: block;
  margin-bottom: 6px;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.fc-recall-input {
  width: 100%;
  min-height: 96px;
  max-height: 34vh;
  padding: 10px 12px;
  border: 1px solid var(--line);
  background: var(--panel);
  font: inherit;
  font-size: 14px;
  line-height: 1.45;
  resize: none;
  overflow: hidden;
}

.fc-recall-input:focus {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.fc-recall-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.fc-recall-result {
  margin-top: 12px;
}

.fc-study-back {
  border-top: 1px dashed var(--line);
  margin-top: 18px;
  padding-top: 18px;
  color: var(--ink);
  font-weight: 400;
}

.fc-study-foot {
  display: flex;
  gap: 8px;
  justify-content: center;
  flex-wrap: wrap;
}

.fc-study-show {
  min-width: 220px;
}

.fc-rate {
  flex: 1 1 0;
  min-width: 110px;
  padding: 10px 14px;
  font-weight: 700;
}

.fc-rate-again { color: #7f1d1d; border-color: #f87171; }
.fc-rate-hard  { color: #78350f; border-color: #f59e0b; }
.fc-rate-good  { color: #14532d; border-color: #4ade80; }
.fc-rate-easy  { background: var(--accent); color: var(--paper); border-color: var(--accent); }

.fc-rate:hover { transform: translateY(-1px); }

.toc-actions {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 10px 0;
  padding: 8px;
  background: var(--paper);
  border: 1px solid var(--line);
}

.toc-source {
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 10px;
  font-weight: 700;
}

.toc-build-btn {
  border: 1px solid var(--accent);
  background: var(--accent);
  color: var(--paper);
  padding: 6px 10px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
}

.toc-build-btn:hover {
  background: #2a3a30;
}

/* ----- Sidebar tools ----- */
.nav-divider {
  margin-top: 18px;
  padding: 6px 12px 4px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
  font-weight: 700;
}

.nav-tool {
  display: block;
  padding: 8px 12px;
  border: 1px solid transparent;
  font-size: 14px;
}

.nav-tool:hover,
.nav-tool.active {
  background: var(--panel-2);
  border-color: var(--line);
}

/* ----- Dashboard practice strip ----- */
.practice-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin: 24px 0;
}

.practice-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 120px;
}

.practice-card .eyebrow { margin: 0; }
.practice-card strong { font-size: 38px; line-height: 1; font-weight: 800; }
.practice-card small { color: var(--muted); font-size: 12px; }
.practice-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }

.sr-card { border-top-color: #365f8f; }
.mistakes-card { border-top-color: #a84f3d; }
.mocks-card { border-top-color: #755a9b; }

/* ----- Page wrap (mistake bank / SR / mocks) ----- */
.page-wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 8px 4px 60px;
}

.page-hero {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent);
  padding: 22px 26px;
  box-shadow: var(--shadow);
  margin-bottom: 22px;
}

.page-hero h1 {
  font-size: clamp(34px, 4vw, 56px);
  margin: 8px 0 8px;
}

.page-hero .eyebrow a {
  color: var(--muted);
}

/* ----- Mistake bank ----- */
.mistake-group {
  margin-top: 20px;
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 18px 22px;
}

.mistake-group h2 {
  font-size: 20px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
}

.mistake-group h2 small {
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
}

.mistake-card {
  border: 1px solid var(--line);
  border-left: 4px solid var(--danger);
  background: var(--paper);
  padding: 14px 16px;
  margin-bottom: 14px;
}

.mistake-head {
  display: flex;
  gap: 8px;
  align-items: center;
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.mistake-score {
  border: 1px solid var(--danger);
  color: var(--danger);
  background: rgba(168, 79, 61, 0.1);
  padding: 2px 7px;
  font-weight: 700;
}

.mistake-source { font-style: italic; }
.mistake-when { margin-left: auto; }

.mistake-question {
  font-size: 14px;
  margin-bottom: 8px;
  line-height: 1.5;
}

.mistake-attempt {
  background: var(--panel);
  padding: 8px 10px;
  font-size: 12px;
  white-space: pre-wrap;
  margin: 4px 0 0;
}

.mistake-card details {
  margin: 8px 0;
}

.mistake-card details summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 13px;
  padding: 4px 0;
}

.mistake-actions {
  display: flex;
  gap: 6px;
  margin-top: 10px;
  flex-wrap: wrap;
}

.mistake-resolve, .mistake-delete {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 6px 12px;
  font-size: 12px;
  cursor: pointer;
}

.mistake-resolve {
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 700;
}

.mistake-resolve:hover {
  background: var(--accent);
  color: var(--paper);
}

.mistake-delete { color: var(--muted); }

/* ----- SR review ----- */
.sr-page .page-hero { border-top-color: #365f8f; }

.sr-empty {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 40px 28px;
  text-align: center;
}

.sr-empty h2 { margin-bottom: 8px; }

.sr-card-view {
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 4px solid #365f8f;
  padding: 26px 30px;
}

.sr-meta {
  display: flex;
  gap: 10px;
  align-items: center;
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.sr-stats { margin-left: auto; font-family: SFMono-Regular, Consolas, monospace; }

.sr-remove-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--muted);
  font-size: 11px;
  padding: 4px 8px;
  cursor: pointer;
  transition: all 0.15s;
  font-family: inherit;
}
.sr-remove-btn:hover {
  background: #fef2f2;
  border-color: #fca5a5;
  color: #b91c1c;
}

.sr-question {
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 24px;
  line-height: 1.4;
  margin-bottom: 18px;
  color: var(--ink);
}

.sr-options {
  list-style: lower-alpha;
  padding-left: 28px;
  margin: 10px 0 20px;
  font-size: 16px;
}

.sr-actions {
  display: flex;
  gap: 10px;
  margin-top: 20px;
}

.sr-answer {
  margin-top: 18px;
  padding: 14px 16px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
}

.sr-answer h4 {
  margin: 0 0 8px;
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.sr-rate {
  margin-top: 20px;
}

.sr-rate p { margin-bottom: 10px; font-weight: 600; }

.sr-rate-buttons {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 6px;
}

.sr-q-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 10px;
  font-weight: 700;
  font-size: 18px;
  cursor: pointer;
}

.sr-q-btn small {
  font-size: 10px;
  font-weight: 500;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.sr-q-btn:hover { border-color: var(--ink); }
.sr-q-0, .sr-q-1, .sr-q-2 { background: #f0c8c0; }
.sr-q-3 { background: #f3e2c8; }
.sr-q-4 { background: #dfeae4; }
.sr-q-5 { background: #c4dec8; }

/* ----- Mock results ----- */
.mocks-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--panel);
  border: 1px solid var(--line);
  font-size: 14px;
}

.mocks-table th,
.mocks-table td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
}

.mocks-table th {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* ----- Per-question SR button ----- */
.q-sr {
  border: 1px solid #365f8f;
  background: var(--paper);
  color: #365f8f;
  padding: 8px 14px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.q-sr:hover { background: #365f8f; color: var(--paper); }
.q-sr:disabled { opacity: 0.6; cursor: default; }
.q-sr.q-sr-added {
  background: #f0fdf4;
  border-color: #86efac;
  color: #166534;
}
.q-sr.q-sr-added:hover { background: #f0fdf4; color: #166534; }

/* ----- Mini-mock overlay ----- */
.mock-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 22, 17, 0.7);
  z-index: 100;
  display: grid;
  place-items: center;
  padding: 24px;
}

.mock-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 5px solid var(--accent);
  padding: 24px 28px;
  width: min(900px, 100%);
  max-height: calc(100vh - 48px);
  overflow-y: auto;
  box-shadow: 0 30px 80px rgba(0,0,0,0.4);
}

.mock-panel h2 {
  margin-top: 0;
  font-size: 24px;
}

.mock-head {
  display: flex;
  align-items: center;
  gap: 14px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 18px;
  font-size: 13px;
  flex-wrap: wrap;
}

.mock-head strong {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.mock-timer {
  margin-left: auto;
  font-family: SFMono-Regular, Consolas, monospace;
  font-weight: 700;
  font-size: 16px;
  background: var(--ink);
  color: var(--paper);
  padding: 6px 12px;
}

.mock-question {
  margin-bottom: 16px;
}

.mock-question .q-body {
  font-size: 16px;
  margin-bottom: 12px;
  line-height: 1.5;
}

.mock-foot {
  display: flex;
  gap: 8px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  margin-top: 18px;
  align-items: center;
}

.mock-foot .load-q-btn {
  margin-left: auto;
}

.mock-panel.results .mock-results-list {
  list-style: none;
  padding: 0;
  margin: 16px 0;
  display: grid;
  gap: 6px;
}

.mock-panel.results .mock-results-list li {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 8px 10px;
  font-size: 14px;
}

.extend-field {
  border: 1px solid var(--line);
  padding: 12px 14px;
  margin: 12px 0;
}

.extend-field legend {
  padding: 0 6px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  font-weight: 700;
}

.extend-types {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 6px;
  margin-bottom: 6px;
}

.extend-type-chk,
.extend-count-radio {
  display: flex;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--line);
  padding: 8px 12px;
  background: var(--paper);
  cursor: pointer;
  font-size: 14px;
}

.extend-type-chk:hover,
.extend-count-radio:hover {
  border-color: var(--ink);
}

.extend-type-chk input:checked + span,
.extend-count-radio input:checked + span {
  font-weight: 700;
}

.extend-counts {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.extend-count-radio {
  min-width: 60px;
  justify-content: center;
}

.extend-actions {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}

.extend-actions .load-q-btn {
  flex: 1;
}

.extend-custom-prompt {
  width: 100%;
  box-sizing: border-box;
  padding: 10px 12px;
  border: 1px solid var(--line);
  background: var(--paper);
  font-family: inherit;
  font-size: 13px;
  line-height: 1.5;
  resize: vertical;
  min-height: 80px;
  color: var(--ink);
}

.extend-custom-prompt:focus {
  outline: none;
  border-color: var(--ink);
}

.extend-custom-prompt::placeholder {
  color: var(--muted);
  font-style: italic;
}

.regen-warning {
  background: #fff8e6;
  border: 1px solid #f59e0b;
  border-left-width: 4px;
  color: #92400e;
  padding: 10px 14px;
  font-size: 13px;
  line-height: 1.5;
  margin: 12px 0;
}

.regen-submit-btn {
  background: #b45309 !important;
  border-color: #b45309 !important;
}

.regen-submit-btn:hover {
  background: #92400e !important;
  border-color: #92400e !important;
}

/* ----- Custom multi-select dropdown (question filters) ----- */
.multi-dd {
  position: relative;
  display: inline-block;
}

.multi-dd-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--paper);
  border: 1px solid var(--line);
  color: var(--ink);
  font-family: inherit;
  font-size: 13px;
  padding: 6px 10px 6px 12px;
  cursor: pointer;
  white-space: nowrap;
  transition: border-color 0.12s, background 0.12s;
}

.multi-dd-toggle:hover {
  border-color: var(--ink);
}

.multi-dd.is-open .multi-dd-toggle {
  border-color: var(--ink);
  background: var(--paper);
}

.multi-dd-toggle.has-selection .multi-dd-label {
  font-weight: 600;
}

.multi-dd-arrow {
  font-size: 9px;
  color: var(--muted);
  transition: transform 0.15s;
}

.multi-dd.is-open .multi-dd-arrow {
  transform: rotate(180deg);
}

.multi-dd-panel {
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  min-width: 180px;
  background: var(--paper);
  border: 1px solid var(--line);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.08), 0 2px 4px rgba(0, 0, 0, 0.06);
  padding: 6px;
  z-index: 100;
  max-height: 320px;
  overflow-y: auto;
}

.multi-dd-actions {
  display: flex;
  gap: 4px;
  padding: 2px 2px 6px 2px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 4px;
}

.multi-dd-action {
  flex: 1;
  background: transparent;
  border: 1px solid transparent;
  color: var(--muted);
  font-family: inherit;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 600;
  padding: 4px 6px;
  cursor: pointer;
  transition: background 0.1s, color 0.1s;
}

.multi-dd-action:hover {
  background: var(--panel);
  color: var(--ink);
}

.multi-dd-option {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 8px;
  font-size: 13px;
  cursor: pointer;
  user-select: none;
  transition: background 0.08s;
}

.multi-dd-option:hover {
  background: var(--panel);
}

.multi-dd-option input[type="checkbox"] {
  width: 14px;
  height: 14px;
  margin: 0;
  flex-shrink: 0;
  cursor: pointer;
  accent-color: #365f8f;
}

.multi-dd-option span {
  color: var(--ink);
}

/* ----- Progress tracker card ----- */
.q-progress {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 14px 16px;
  margin: 16px 0;
  display: grid;
  grid-template-columns: minmax(140px, 200px) 1fr;
  gap: 16px;
  align-items: center;
}

.q-progress-meta .eyebrow {
  margin: 0 0 4px 0;
}

.q-progress-line {
  margin: 0;
  font-size: 13px;
  color: var(--ink);
  line-height: 1.4;
}

.q-progress-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

.q-progress-cell {
  width: 28px;
  height: 28px;
  padding: 0;
  border: 1px solid transparent;
  font-family: inherit;
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  color: var(--ink);
  transition: transform 0.08s, box-shadow 0.08s, border-color 0.08s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.q-progress-cell:hover {
  transform: translateY(-1px);
  box-shadow: 0 2px 4px rgba(0,0,0,0.12);
}

.q-progress-cell.is-current {
  outline: 2px solid var(--ink);
  outline-offset: 1px;
}

/* Color buckets — also used inside the legend swatches */
.q-progress-unanswered {
  background: #e5e7eb;
  border-color: #d1d5db;
  color: #6b7280;
}
.q-progress-low {
  background: #fecaca;
  border-color: #f87171;
  color: #7f1d1d;
}
.q-progress-mid {
  background: #fde68a;
  border-color: #f59e0b;
  color: #78350f;
}
.q-progress-good {
  background: #bbf7d0;
  border-color: #4ade80;
  color: #14532d;
}
.q-progress-great {
  background: #16a34a;
  border-color: #15803d;
  color: #ffffff;
}

.q-progress-legend {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 4px;
  padding-top: 8px;
  border-top: 1px dashed var(--line);
  font-size: 10px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.q-legend-item {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.q-legend-swatch {
  display: inline-block;
  width: 10px;
  height: 10px;
  border: 1px solid transparent;
}

@media (max-width: 700px) {
  .q-progress {
    grid-template-columns: 1fr;
  }
}

/* ----- Mock start button in questions panel ----- */
.sr-bulk-btn {
  border-color: #365f8f !important;
  background: #365f8f !important;
}

.sr-bulk-btn:hover {
  background: #284e72 !important;
  border-color: #284e72 !important;
}

.mocks-empty {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 24px 28px;
}

.mocks-empty h3 {
  margin-top: 0;
  font-size: 24px;
}

.mocks-empty-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
  margin-top: 18px;
}

.mocks-empty-course strong {
  display: block;
  margin-bottom: 8px;
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.mocks-empty-course ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 4px;
}

.mocks-empty-course li a {
  display: block;
  padding: 6px 10px;
  border: 1px solid var(--line);
  background: var(--paper);
  font-size: 13px;
}

.mocks-empty-course li a:hover {
  border-color: var(--ink);
}

.mock-start-btn {
  border-color: #755a9b !important;
  background: #755a9b !important;
}

.mock-start-btn:hover {
  background: #5a4476 !important;
  border-color: #5a4476 !important;
}

.markdown-body {
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 17px;
  line-height: 1.6;
  color: var(--ink);
  max-width: 820px;
  min-width: 0;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  font-family: Avenir Next, Optima, Candara, Segoe UI, sans-serif;
  line-height: 1.2;
  margin: 1.6em 0 0.4em;
}

.markdown-body h1 { font-size: 30px; }
.markdown-body h2 { font-size: 24px; border-bottom: 1px solid var(--line); padding-bottom: 6px; }
.markdown-body h3 { font-size: 19px; }
.markdown-body h4 { font-size: 16px; }

.markdown-body p { margin: 0 0 1em; }

.markdown-body ul,
.markdown-body ol {
  margin: 0 0 1em;
  padding-left: 1.5em;
}

.markdown-body code {
  font-family: SFMono-Regular, Consolas, Liberation Mono, monospace;
  font-size: 0.88em;
  background: var(--paper);
  padding: 1px 5px;
  border: 1px solid var(--line);
  color: #2a3a30;
}

.markdown-body pre {
  background: #f6f8fa;
  border: 1px solid var(--line);
  padding: 12px 14px;
  overflow-x: auto;
  margin: 0 0 1em;
}

.markdown-body pre code {
  background: transparent;
  border: 0;
  padding: 0;
  font-size: 13px;
}

.md-table-wrap {
  max-width: 100%;
  overflow-x: auto;
  overflow-y: hidden;
  margin: 0 0 1em;
  border: 1px solid var(--line);
  background: var(--panel);
  scrollbar-gutter: stable;
}

.markdown-body table {
  border-collapse: collapse;
  margin: 0;
  width: 100%;
  font-size: 15px;
}

.md-table-wrap.is-wide table {
  min-width: 680px;
}

.markdown-body table th,
.markdown-body table td {
  border: 1px solid var(--line);
  padding: 8px 10px;
  vertical-align: top;
  overflow-wrap: anywhere;
  hyphens: auto;
}

.markdown-body table th {
  background: var(--paper);
  text-align: left;
  font-family: Avenir Next, Optima, Candara, Segoe UI, sans-serif;
}

.markdown-body blockquote {
  border-left: 4px solid var(--line);
  margin: 0 0 1em;
  padding: 4px 14px;
  background: var(--paper);
  color: #3a443a;
}

.markdown-body .wikilink {
  background: rgba(59, 111, 91, 0.1);
  border: 1px dashed rgba(59, 111, 91, 0.4);
  padding: 0 4px;
  font-size: 0.95em;
}

.markdown-body details.callout {
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
  padding: 6px 14px;
  margin: 0 0 1em;
  background: var(--paper);
}

.markdown-body details.callout summary {
  cursor: pointer;
  font-weight: 700;
  font-family: Avenir Next, Optima, Candara, Segoe UI, sans-serif;
}

.markdown-body details.callout[open] > summary {
  margin-bottom: 6px;
}

.markdown-body details.callout-warning,
.markdown-body details.callout-danger,
.markdown-body details.callout-bug {
  border-left-color: var(--danger);
}

.markdown-body details.callout-info,
.markdown-body details.callout-note {
  border-left-color: #365f8f;
}

.markdown-body details.callout-tip,
.markdown-body details.callout-success {
  border-left-color: #3b6f5b;
}

.markdown-body .katex-display {
  margin: 1em 0;
  overflow-x: auto;
  overflow-y: hidden;
}

.mermaid-block {
  margin: 1em 0;
  padding: 14px;
  background: var(--paper);
  border: 1px solid var(--line);
  text-align: center;
  overflow-x: auto;
}

.mermaid-block svg {
  max-width: 100%;
  height: auto;
}

.mermaid-error {
  text-align: left;
  background: rgba(168, 79, 61, 0.06);
  border-color: var(--danger);
  color: var(--danger);
  font-size: 12px;
}

.topic-aside .mermaid-block {
  margin: 0 0 12px;
}

.markdown-body.topical {
  max-width: none;
  container-type: inline-size;
}

.topic-card {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 18px 22px;
  margin: 0 0 18px;
}

.topic-card > h2 {
  margin-top: 0;
  border-bottom: 1px solid var(--line);
  padding-bottom: 8px;
}

.topic-flex {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 22px;
  align-items: start;
}

.topic-prose,
.topic-aside {
  min-width: 0;
}

.topic-aside {
  position: sticky;
  top: 70px;
  padding: 14px;
  background: #faf8f1;
  border: 1px solid var(--line);
}

.topic-aside pre {
  margin: 0 0 12px;
}

.topic-aside pre:last-child {
  margin-bottom: 0;
}

.topic-aside table {
  margin-bottom: 0;
}

.topic-pre {
  margin-bottom: 18px;
}

@container (max-width: 980px) {
  .topic-flex {
    grid-template-columns: 1fr;
  }

  .topic-aside {
    position: static;
    padding: 0;
    background: transparent;
    border: 0;
  }
}

@container (max-width: 720px) {
  .topic-card {
    padding: 14px 16px;
  }

  .markdown-body table {
    font-size: 13px;
  }

  .markdown-body table th,
  .markdown-body table td {
    padding: 7px 8px;
  }
}

.examples-panel {
  margin-top: 32px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 5px solid var(--accent);
  padding: 22px 26px;
}

.examples-panel .panel-head {
  margin-bottom: 12px;
}

.questions-panel {
  margin-top: 32px;
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 22px 26px;
}

.questions-panel .panel-head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.q-panel-head h2 {
  margin: 0 0 6px;
}

.type-strip {
  display: flex;
  gap: 4px;
}

.type-pip {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 3px 7px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--ink);
}

.type-pip small {
  font-weight: 700;
  font-size: 11px;
  color: var(--muted);
}

.type-pip.zero {
  opacity: 0.4;
}

.type-pip.type-written { background: #eef0ea; }
.type-pip.type-calc { background: #f3e2c8; }
.type-pip.type-tf { background: #e6e0f0; }
.type-pip.type-mc { background: #dfeae4; }
.type-pip.type-pseudocode { background: #f0e0d8; }

.q-toolbar {
  display: flex;
  gap: 6px;
  margin-left: auto;
  align-items: center;
  flex-wrap: wrap;
}

/* ===== Unified button system =====
   Three weights matching the app's existing palette:
   - .btn          base styling
   - .btn-primary  filled accent (one per region — the main action)
   - .btn-ghost    outlined, low-emphasis (default for secondary actions)
   - .btn-danger   red, destructive
   - .btn-success  used for "already done" indicator states
   - .btn-secondary  cancel buttons
   .tb-btn (toolbar button) follows .btn-ghost rules, slightly smaller.
*/
.btn,
.tb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  height: 32px;
  padding: 0 14px;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink);
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.12s, border-color 0.12s, color 0.12s;
  white-space: nowrap;
}

.btn:hover,
.tb-btn:hover {
  border-color: var(--ink);
  background: var(--paper);
}

.btn:disabled,
.tb-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.btn:disabled:hover {
  border-color: var(--line);
  background: var(--panel);
}

.btn.btn-primary,
.tb-btn.tb-btn-primary {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
  font-weight: 600;
}

.btn.btn-primary:hover,
.tb-btn.tb-btn-primary:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}

.btn-ghost {
  background: transparent;
}

.btn-ghost:hover {
  background: var(--panel);
  border-color: var(--ink);
}

.btn-success {
  background: #ecf3ee;
  border-color: #86b09a;
  color: #2d4f3c;
}

.btn-success:hover {
  background: #ecf3ee;
  border-color: #86b09a;
  color: #2d4f3c;
}

.btn-danger {
  background: #b91c1c;
  border-color: #b91c1c;
  color: #fff;
}

.btn-danger:hover {
  background: #991b1b;
  border-color: #991b1b;
}

.btn-secondary {
  background: transparent;
  border-color: var(--line);
  color: var(--muted);
}

.btn-secondary:hover {
  border-color: var(--ink);
  color: var(--ink);
}

/* ===== Toolbar overflow menu ===== */
.tb-more {
  position: relative;
  display: inline-block;
}

.tb-btn-icon {
  width: 32px;
  padding: 0;
  font-size: 18px;
  line-height: 1;
}

.tb-more.is-open .tb-btn-icon {
  border-color: var(--ink);
  background: var(--paper);
}

/* Three dots drawn with a single pseudo-element + box-shadow.
   No font dependency, no vertical-alignment hacks, no rounded-corner cards. */
.tb-more-glyph {
  position: relative;
  display: inline-block;
  width: 16px;
  height: 4px;
}

.tb-more-glyph::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 3px;
  height: 3px;
  background: currentColor;
  border-radius: 50%;
  transform: translate(-50%, -50%);
  box-shadow: -6px 0 0 currentColor, 6px 0 0 currentColor;
}

.tb-more-menu {
  position: absolute;
  top: calc(100% + 4px);
  right: 0;
  min-width: 260px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 0 12px 28px rgba(0, 0, 0, 0.14), 0 4px 8px rgba(0, 0, 0, 0.06);
  z-index: 100;
  padding: 4px;
}

.tb-more-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  width: 100%;
  padding: 10px 12px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--ink);
  font-family: inherit;
  font-size: 13px;
  text-align: left;
  cursor: pointer;
  transition: background 0.12s, color 0.12s;
}

.tb-more-item:hover {
  background: var(--paper);
}

.tb-more-item strong {
  display: block;
  font-weight: 600;
  margin-bottom: 2px;
  color: var(--ink);
  font-size: 13px;
}

.tb-more-item small {
  display: block;
  color: var(--muted);
  font-size: 11.5px;
  line-height: 1.4;
}

.tb-more-icon {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 15px;
  color: var(--muted);
  margin-top: 1px;
}

.tb-more-divider {
  height: 1px;
  background: var(--line);
  margin: 4px 0;
}

.tb-more-danger:hover {
  background: #fef2f2;
}

.tb-more-danger:hover strong {
  color: #b91c1c;
}

.tb-more-danger:hover .tb-more-icon {
  color: #b91c1c;
}

/* ===== Custom confirm modal ===== */
.confirm-overlay {
  position: fixed;
  inset: 0;
  background: rgba(22, 32, 25, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1100;
  padding: 32px;
  animation: confirm-fade-in 0.12s ease-out;
}

@keyframes confirm-fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

.confirm-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 5px solid var(--accent);
  max-width: 440px;
  width: 100%;
  padding: 24px 26px 20px;
  box-shadow: 0 30px 80px rgba(0,0,0,0.4);
  animation: confirm-pop-in 0.16s ease-out;
}

@keyframes confirm-pop-in {
  from { transform: translateY(4px) scale(0.98); opacity: 0; }
  to   { transform: translateY(0) scale(1); opacity: 1; }
}

.confirm-title {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.confirm-message {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
}

.confirm-actions {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
}

.confirm-actions .btn {
  min-width: 96px;
}

.q-toolbar select,
.q-toolbar button {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 6px 10px;
  font-size: 13px;
}

.q-toolbar .regen-btn,
button.regen-btn {
  cursor: pointer;
  font-weight: 700;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: var(--paper);
  padding: 6px 12px;
}

.q-toolbar .regen-btn:hover,
button.regen-btn:hover {
  background: #2a3a30;
  border-color: #2a3a30;
  color: var(--paper);
}

.q-toolbar .extend-btn,
button.extend-btn {
  cursor: pointer;
  font-weight: 700;
  border: 1px solid #365f8f;
  background: #365f8f;
  color: var(--paper);
  padding: 6px 12px;
}

.q-toolbar .extend-btn:hover,
button.extend-btn:hover {
  background: #284e72;
  border-color: #284e72;
}

.q-pager {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  margin: 0 0 14px;
  background: var(--paper);
  border: 1px solid var(--line);
  flex-wrap: wrap;
}

.q-pager-pos {
  font-size: 13px;
  color: var(--muted);
  padding: 0 8px;
  margin-right: auto; /* push subsequent items (Random, Next) to the right edge */
}

.q-pager-pos strong {
  color: var(--ink);
  font-size: 15px;
}

.q-jump {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 6px 10px;
  font-size: 13px;
  flex: 1 1 200px;
  min-width: 180px;
}

.q-nav-btn {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 8px 14px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.q-nav-btn:hover:not(:disabled) {
  border-color: var(--ink);
}

.q-nav-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.q-nav-btn.primary {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.q-nav-btn.primary:hover:not(:disabled) {
  background: #2a3a30;
}

.single-question .question-card {
  margin: 0;
}

.load-q-btn {
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--paper);
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
}

.load-q-btn:hover {
  background: #2a3a30;
}

.loader {
  padding: 24px;
  border: 1px dashed var(--line);
  background: var(--paper);
  color: var(--muted);
  font-size: 14px;
}

.loader.error {
  color: var(--danger);
  border-color: var(--danger);
}

.question-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 14px;
}

.question-card {
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 18px 22px;
}

.q-head {
  display: flex;
  gap: 10px;
  align-items: center;
  font-size: 12px;
  margin-bottom: 10px;
  color: var(--muted);
  justify-content: space-between;
}

.q-head-left {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}

.q-delete {
  background: transparent;
  border: 1px solid transparent;
  color: var(--muted);
  font-size: 18px;
  line-height: 1;
  width: 28px;
  height: 28px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  flex-shrink: 0;
  transition: background 0.12s, color 0.12s, border-color 0.12s;
}

.q-delete:hover {
  background: #fef2f2;
  border-color: #fca5a5;
  color: #b91c1c;
}

.q-num {
  font-weight: 800;
  font-size: 13px;
  color: var(--ink);
}

.q-type {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 2px 7px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 10px;
  font-weight: 700;
}

.q-diff {
  border: 1px solid var(--line);
  padding: 2px 6px;
  text-transform: uppercase;
  font-size: 10px;
  font-weight: 700;
}

.q-diff.diff-easy { background: #d8e8d8; color: #2c4b34; }
.q-diff.diff-medium { background: #f3e2c8; color: #6e4f1f; }
.q-diff.diff-hard { background: #f0c8c0; color: #6f3526; }

.q-source {
  font-style: italic;
}

.q-body {
  font-size: 15px;
  margin-bottom: 10px;
  line-height: 1.5;
}

.q-body p {
  margin: 0;
}

.q-options {
  display: grid;
  gap: 6px;
  margin-bottom: 10px;
}

/* Block label with the radio/checkbox absolutely positioned. This keeps the
   text + inline `.katex` spans as ordinary inline content, so they wrap on
   ordinary line boundaries instead of each math span and each word becoming
   its own "column". (Previously `display: flex` turned every contiguous
   text run between `.katex` spans into a separate anonymous flex item.) */
.q-options label {
  display: block;
  position: relative;
  padding: 6px 10px 6px 30px;
  border: 1px solid var(--line);
  background: var(--panel);
  cursor: pointer;
  line-height: 1.45;
}

.q-options label > input[type="radio"],
.q-options label > input[type="checkbox"] {
  position: absolute;
  left: 8px;
  top: 10px;
  margin: 0;
}

.q-options label:hover {
  border-color: var(--ink);
}

.q-input {
  width: 100%;
  min-height: 112px;
  max-height: 52vh;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 10px 12px;
  font-family: inherit;
  font-size: 14px;
  line-height: 1.45;
  resize: none;
  overflow: hidden;
  margin-bottom: 10px;
}

/* ----- Image attachment drop zone ----- */
.attempt-drop {
  position: relative;
  border: 1px dashed transparent;
  padding: 2px;
  transition: border-color 0.15s, background 0.15s;
}

.attempt-drop.drop-hover {
  border-color: var(--accent);
  background: rgba(59, 111, 91, 0.08);
}

.attempt-drop > .q-input {
  margin-bottom: 6px;
}

.attempt-drop-hint {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  color: var(--muted);
  cursor: pointer;
  padding: 4px 8px;
  border: 1px solid var(--line);
  background: var(--paper);
  margin: 4px 0 6px;
}

.attempt-drop-hint:hover {
  border-color: var(--accent);
  color: var(--ink);
}

.attempt-file-input {
  padding: 0 !important;
  border: 0 !important;
  background: transparent !important;
  font-size: 11px;
  width: auto;
  min-height: auto !important;
  margin: 0 !important;
}

.attempt-thumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 6px 0 4px;
}

.attempt-thumb {
  position: relative;
  width: 88px;
  height: 88px;
  border: 1px solid var(--line);
  background: var(--paper);
  overflow: hidden;
}

.attempt-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.attempt-thumb-remove {
  position: absolute;
  top: 3px;
  right: 3px;
  width: 22px;
  height: 22px;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--paper);
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
  display: grid;
  place-items: center;
  padding: 0;
  border-radius: 50%;
}

.attempt-thumb-remove:hover {
  background: var(--danger);
  border-color: var(--danger);
}

.q-input.code {
  font-family: SFMono-Regular, Consolas, Liberation Mono, monospace;
  font-size: 13px;
  min-height: 160px;
}

.q-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.q-submit,
.q-reveal {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 8px 14px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.q-submit {
  border-color: var(--ink);
  background: var(--ink);
  color: var(--paper);
}

.q-submit:disabled {
  background: var(--muted);
  border-color: var(--muted);
  cursor: wait;
}

.q-grade,
.q-expected {
  margin-top: 14px;
  font-size: 14px;
}

.q-grade {
  padding: 14px 16px;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 78%, var(--paper));
}

.q-expected {
  padding-top: 12px;
  border-top: 1px dashed var(--line);
}

.q-grade > strong:first-child,
.q-expected > strong:first-child {
  display: block;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0 0 8px;
}

.q-score-line {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin: 0 0 12px;
  padding: 4px 8px;
  border: 1px solid var(--line);
  background: var(--paper);
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  font-size: 12px;
  font-weight: 800;
  color: var(--ink);
}

.q-score-line strong {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.q-grade h1,
.q-grade h2,
.q-grade h3,
.q-grade h4,
.q-grade p:has(> strong:first-child:last-child) {
  margin: 14px 0 6px;
  font-family: Avenir Next, Optima, Candara, "Segoe UI", sans-serif;
  font-size: 13px;
  font-weight: 800;
  text-transform: none;
  letter-spacing: 0;
  color: var(--ink);
}

.q-grade h1:first-child,
.q-grade h2:first-child,
.q-grade h3:first-child,
.q-grade h4:first-child,
.q-grade p:has(> strong:first-child:last-child):first-child {
  margin-top: 0;
}

.q-grade p,
.q-expected p {
  margin: 0 0 8px;
  line-height: 1.5;
}

.q-grade p:last-child,
.q-expected p:last-child {
  margin-bottom: 0;
}

.q-grade ul,
.q-grade ol {
  margin: 6px 0 12px;
  padding-left: 20px;
}

.q-grade li {
  margin: 4px 0;
  line-height: 1.45;
}

.q-grade code {
  font-size: 0.92em;
}

@media (max-width: 1400px) {
  .chapter-grid {
    grid-template-columns: minmax(170px, var(--toc-width, 210px)) 6px minmax(0, 1fr) 6px minmax(300px, var(--rail-width, 340px));
    gap: 8px;
    padding-inline: 18px;
  }
  :root[data-rail-collapsed="true"] .chapter-grid {
    grid-template-columns: minmax(170px, var(--toc-width, 210px)) 6px minmax(0, 1fr) 0 36px;
  }
  :root[data-toc-collapsed="true"] .chapter-grid {
    grid-template-columns: 36px 0 minmax(0, 1fr) 6px minmax(300px, var(--rail-width, 340px));
  }
  :root[data-toc-collapsed="true"][data-rail-collapsed="true"] .chapter-grid {
    grid-template-columns: 36px 0 minmax(0, 1fr) 0 36px;
  }
  .chapter-rail {
    grid-column: auto;
    height: 100%;
    display: flex;
    gap: 14px;
  }
  .chat-panel {
    grid-column: auto;
    min-height: 0;
  }
}

@media (max-width: 1000px) {
  .chapter-grid {
    gap: 6px;
    padding: 12px 10px;
  }
  :root[data-rail-collapsed="true"] .chapter-grid {
    grid-template-columns: minmax(150px, min(var(--toc-width, 190px), 190px)) 0 minmax(0, 1fr) 0 32px;
  }
  :root[data-toc-collapsed="true"] .chapter-grid {
    grid-template-columns: 32px 0 minmax(0, 1fr) 0 minmax(280px, min(var(--rail-width, 320px), 320px));
  }
  :root[data-toc-collapsed="true"][data-rail-collapsed="true"] .chapter-grid {
    grid-template-columns: 32px 0 minmax(0, 1fr) 0 32px;
  }
  .chapter-toc,
  .chapter-rail {
    padding-inline: 6px;
  }
  :root[data-toc-collapsed="true"] .chapter-toc,
  :root[data-rail-collapsed="true"] .chapter-rail {
    padding-inline: 0;
  }
  .chapter-hero {
    padding: 16px 18px;
    margin-bottom: 14px;
  }
  .chapter-hero h1 {
    font-size: clamp(28px, 5vw, 38px);
  }
  .surface-tabs {
    gap: 6px;
  }
  .surface-tab {
    padding: 7px 11px;
    font-size: 13px;
  }
  .surface-tabs-divider {
    display: none;
  }
  .markdown-body {
    font-size: 16px;
  }
  .topic-card {
    padding: 14px 16px;
  }

  .chapter-grid.course-home-grid,
  :root[data-toc-collapsed="true"] .chapter-grid.course-home-grid,
  :root[data-rail-collapsed="true"] .chapter-grid.course-home-grid,
  :root[data-toc-collapsed="true"][data-rail-collapsed="true"] .chapter-grid.course-home-grid {
    grid-template-columns: 1fr;
  }

  .chapter-grid.course-home-grid > .resize-handle {
    display: none;
  }

  .chapter-grid.course-home-grid .chapter-toc.course-toc {
    display: none;
  }

  .course-home-main .course-hero {
    grid-template-columns: minmax(0, 1fr);
    min-height: 0;
  }

  .course-home-main .hero-meter {
    width: min(190px, 100%);
    aspect-ratio: auto;
    min-height: 132px;
  }

  .surface-hero {
    display: flex;
    flex-direction: column;
    align-items: stretch;
  }
  .surface-hero .hero-meter { width: min(160px, 100%); }
}

@media (max-width: 1100px) {
  .chapter-grid.course-home-grid,
  :root[data-toc-collapsed="true"] .chapter-grid.course-home-grid,
  :root[data-rail-collapsed="true"] .chapter-grid.course-home-grid,
  :root[data-toc-collapsed="true"][data-rail-collapsed="true"] .chapter-grid.course-home-grid {
    grid-template-columns: 1fr;
  }

  .chapter-grid.course-home-grid > .resize-handle,
  .chapter-grid.course-home-grid .chapter-toc.course-toc {
    display: none;
  }

  .course-home-main {
    height: auto;
    overflow: visible;
  }

  .course-home-main .course-hero {
    grid-template-columns: minmax(0, 1fr);
    min-height: 0;
  }
}

@media (max-width: 820px) {
  .shell {
    grid-template-columns: var(--sidebar-width, 64px) 0 minmax(0, 1fr);
  }
  .shell > .resize-handle { display: none; }
  .chapter-grid {
    grid-template-columns: minmax(0, 1fr);
    overflow: hidden;
  }
  :root[data-toc-collapsed="true"] .chapter-grid,
  :root[data-rail-collapsed="true"] .chapter-grid,
  :root[data-toc-collapsed="true"][data-rail-collapsed="true"] .chapter-grid {
    grid-template-columns: minmax(0, 1fr);
  }
  .chapter-grid .resize-handle { display: none; }
  .chapter-grid > .chapter-toc,
  .chapter-grid > .chapter-rail {
    display: none;
  }
  .chapter-main {
    height: 100%;
    overflow-y: auto;
    overflow-x: hidden;
  }
  .topic-flex {
    grid-template-columns: 1fr;
  }
  .topic-aside {
    position: static;
  }
}

.trackers {
  margin: 20px 0;
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 12px;
}

.tracker {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 14px;
  display: grid;
  gap: 8px;
}

.tracker strong {
  font-size: 30px;
}

.tracker.muted {
  opacity: 0.45;
}

.course-detail {
  display: grid;
  gap: 20px;
}

.section-heading {
  border-bottom: 1px solid var(--line);
  margin-bottom: 14px;
}

.section-heading h2 {
  font-family: Georgia, Iowan Old Style, serif;
  font-size: 34px;
}

.todo-card {
  border: 1px solid var(--line);
  border-left: 5px solid var(--accent);
  background: #fff;
  padding: 18px;
}

.todo-main {
  display: grid;
  grid-template-columns: 200px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.copy-id {
  cursor: pointer;
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 12px 0;
}

.tag-row span {
  border: 1px solid var(--line);
  background: #f4f1e8;
  padding: 5px 8px;
  color: #4f594f;
  font-size: 13px;
}

.todo-grid {
  margin-top: 12px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.todo-grid > div {
  background: #f7f5ef;
  border: 1px solid var(--line);
  padding: 12px;
}

.todo-grid h4 {
  margin-bottom: 8px;
}

ul {
  margin: 0;
  padding-left: 18px;
}

li + li {
  margin-top: 4px;
}

textarea {
  width: 100%;
  min-height: 118px;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 10px;
  resize: vertical;
  color: var(--ink);
}

@media (max-width: 1180px) {
  .course-grid,
  .trackers,
  .todo-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 800px) {
  .shell {
    grid-template-columns: var(--sidebar-width, 64px) 0 minmax(0, 1fr);
  }

  .sidebar {
    position: relative;
    height: 100vh;
  }

  .hero,
  .course-hero,
  .day-block,
  .course-grid,
  .trackers,
  .todo-grid {
    grid-template-columns: 1fr;
  }

  .content {
    padding: 14px;
  }
}
/* Hosted authentication/bootstrap surface */
.auth-gate {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 2rem;
  background: #f4f1e9;
}

.auth-gate[hidden] { display: none; }
.auth-gate > section { width: min(100%, 28rem); }
.auth-gate h1 { margin: .35rem 0 .65rem; font-size: clamp(2rem, 7vw, 3.5rem); letter-spacing: -.05em; }
.auth-gate p { color: #526058; line-height: 1.55; }
.auth-gate #clerk-sign-in { margin-top: 1.5rem; }
.boot-error { max-width: 42rem; margin: 15vh auto; padding: 2rem; }

/* ==========================================================================
   Wicker Study — academic visual system
   ========================================================================== */
:root {
  --ink: #17243a;
  --muted: #667084;
  --line: #d7d4ca;
  --paper: #f3f0e8;
  --panel: #fffdf8;
  --panel-2: #e9e5dc;
  --accent: #8b2635;
  --accent-deep: #651a27;
  --navy: #12233f;
  --navy-soft: #1d3150;
  --danger: #9d342c;
  --shadow: 0 20px 55px rgba(18, 35, 63, 0.09);
  --shadow-small: 0 8px 24px rgba(18, 35, 63, 0.08);
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  font-synthesis: none;
}

html { scroll-behavior: smooth; }

body {
  background:
    linear-gradient(rgba(23, 36, 58, 0.025) 1px, transparent 1px),
    var(--paper);
  background-size: 100% 32px;
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: rgba(139, 38, 53, 0.17); color: var(--ink); }

.skip-link {
  position: fixed;
  left: 1rem;
  top: 1rem;
  z-index: 100;
  transform: translateY(-200%);
  background: var(--navy);
  color: #fff;
  padding: .7rem 1rem;
  border-radius: 3px;
}
.skip-link:focus { transform: translateY(0); }

:where(a, button, input, textarea, select, summary):focus-visible {
  outline: 3px solid rgba(139, 38, 53, .32);
  outline-offset: 2px;
}

h1, h2, h3, .brand strong, .section-heading h2, .course-section-head h2 {
  font-family: "Source Serif 4", Georgia, serif;
  text-wrap: balance;
}

h1 {
  letter-spacing: -.035em;
  line-height: .98;
  font-weight: 600;
}

.eyebrow {
  color: var(--accent);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .16em;
}

code,
.auth-folio,
.hero-meter span,
.tracker strong,
.spine-summary-pct,
.course-chapter-num {
  font-family: "IBM Plex Mono", monospace;
  font-variant-numeric: tabular-nums;
}

/* Navigation: quiet institutional chrome, clear active location. */
.shell { grid-template-columns: var(--sidebar-width, 286px) 4px minmax(0, 1fr); }

.sidebar {
  padding: 24px 16px 18px;
  background: var(--navy);
  border-right: 0;
  color: #edf0f4;
  gap: 22px;
  scrollbar-color: #53627a transparent;
}

.sidebar-head { min-height: 48px; }
.brand { gap: 11px; }
.brand-mark {
  width: 38px;
  height: 44px;
  background: var(--accent);
  color: #fffaf4;
  border-radius: 2px 2px 9px 2px;
  font-family: "Source Serif 4", serif;
  font-size: 23px;
  font-weight: 600;
  box-shadow: inset 0 -1px 0 rgba(0,0,0,.24);
}
.brand strong { font-size: 16px; font-weight: 600; letter-spacing: -.01em; }
.brand small { color: #aab4c4; font-size: 11px; letter-spacing: .03em; }

.sidebar-toggle {
  width: 30px;
  height: 30px;
  border: 1px solid rgba(255,255,255,.18);
  background: rgba(255,255,255,.04);
  color: #aab4c4;
  border-radius: 3px;
  transition: background .2s ease, border-color .2s ease, color .2s ease;
}
.sidebar-toggle:hover { border-color: rgba(255,255,255,.5); color: #fff; background: rgba(255,255,255,.08); }

.sidebar nav { gap: 3px; }
.nav-dashboard,
.nav-course,
.nav-tool,
.sidebar-search-trigger {
  min-height: 42px;
  border: 0;
  border-left: 2px solid transparent;
  border-radius: 0 4px 4px 0;
  color: #c8d0dc;
  transition: background .18s ease, color .18s ease, border-color .18s ease, transform .18s ease;
}
.nav-dashboard:hover,
.nav-course:hover,
.nav-tool:hover,
.sidebar-search-trigger:hover {
  background: rgba(255,255,255,.065);
  color: #fff;
  border-color: rgba(255,255,255,.28);
  transform: translateX(2px);
}
.nav-dashboard.active,
.nav-course.active,
.nav-tool.active {
  background: rgba(255,255,255,.1);
  color: #fff;
  border-color: #d9a7ae;
}
.nav-course small { color: #8f9db1; }
.nav-course.active small { color: #c9d1dc; }
.nav-icon, .nav-course .nav-icon, .nav-tool .nav-icon, .nav-dashboard .nav-icon { color: #91a0b5; }
.nav-dashboard.active .tool-icon, .nav-tool.active .tool-icon { color: #f3d8dc; }
.nav-divider { color: #7f8da2; margin-top: 12px; }
.nav-divider .nav-label, .nav-archived-toggle .nav-label { font-size: 10px; letter-spacing: .14em; }

.state-card {
  border: 1px solid rgba(255,255,255,.13);
  border-top-color: rgba(255,255,255,.3);
  background: rgba(255,255,255,.045);
  padding: 14px;
  gap: 7px;
  border-radius: 4px;
}
.state-card small { color: #98a5b7; }
.state-card strong { font-family: "Source Serif 4", serif; font-weight: 600; color: #f4f1ea; }
.state-card .legend { line-height: 1.45; }
.sidebar-signout {
  margin-top: 6px;
  padding: 8px 0 0;
  border: 0;
  border-top: 1px solid rgba(255,255,255,.12);
  background: transparent;
  color: #c8d0dc;
  text-align: left;
  font-size: 12px;
  cursor: pointer;
}
.sidebar-signout:hover { color: #fff; }

.resize-handle.vertical-handle::after { background: #8e99a8; }
.resize-handle.vertical-handle:hover::after { background: var(--accent); }

/* Page hierarchy and editorial surfaces. */
.content { padding: clamp(22px, 3vw, 44px); }
.content:not(.chapter-content) > * { width: min(100%, 1420px); margin-inline: auto; }

.hero,
.course-hero {
  min-height: 250px;
  padding: clamp(28px, 4vw, 54px);
  background: var(--panel);
  border: 0;
  border-top: 4px solid var(--navy);
  border-bottom: 1px solid var(--line);
  box-shadow: var(--shadow);
  border-radius: 2px;
}
.course-hero { border-top-color: var(--accent); }
.hero h1, .course-hero h1, .chapter-hero h1 { font-weight: 600; }
.hero-copy { max-width: 60ch; line-height: 1.65; font-size: 17px; }

.hero-meter {
  border: 0;
  border-top: 2px solid var(--accent);
  background: var(--paper);
  box-shadow: inset 0 0 0 1px var(--line);
  border-radius: 2px;
}
.hero-meter span { font-size: 48px; font-weight: 500; letter-spacing: -.07em; }

.course-section-head { margin-top: 38px; padding-bottom: 12px; border-bottom: 1px solid var(--line); }
.course-section-head h2 { font-size: 28px; font-weight: 600; }
.course-grid { margin-top: 18px; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
.course-card {
  min-height: 220px;
  padding: 22px;
  border: 0;
  border-top: 4px solid var(--accent);
  border-bottom: 1px solid var(--line);
  background: var(--panel);
  box-shadow: 0 1px 0 rgba(18,35,63,.04);
  border-radius: 2px;
  transition: transform .22s ease, box-shadow .22s ease, background .22s ease;
}
.course-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-small); background: #fff; }
.course-card h2 { font-family: "Source Serif 4", serif; font-weight: 600; font-size: 26px; }

.practice-strip { gap: 1px; background: var(--line); border: 1px solid var(--line); }
.practice-card { border: 0; background: var(--panel); }
.practice-card:hover { background: #fff; transform: none; }
.practice-card strong { font-family: "IBM Plex Mono", monospace; font-weight: 500; }

.panel,
.rail-card,
.genall-card,
.tracker,
.todo-card,
.examples-panel,
.questions-panel,
.course-spine-section,
.course-toolkit-panel {
  border-color: var(--line);
  border-radius: 3px;
  box-shadow: none;
}
.panel, .rail-card, .tracker, .todo-card { background: var(--panel); }
.tracker { border-top: 2px solid var(--navy); padding: 17px; }
.tracker strong { font-weight: 500; letter-spacing: -.05em; }
.todo-card { border-left-width: 3px; }

.bar, .mini-bar { height: 5px; background: #dedbd2; border-radius: 5px; }
.bar span, .mini-bar span { border-radius: inherit; }

.surface-tabs { gap: 0; border-color: var(--line); }
.surface-tab,
.chapter-subtab,
.toolkit-tab {
  border-radius: 0;
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  transition: color .18s ease, border-color .18s ease, background .18s ease;
}
.surface-tab:hover, .chapter-subtab:hover, .toolkit-tab:hover { background: rgba(23,36,58,.04); }
.surface-tab.active, .chapter-subtab.active, .toolkit-tab.active { border-bottom-color: var(--accent); color: var(--ink); background: transparent; }

.btn, .tb-btn, .q-nav-btn, .load-q-btn, .mock-start-btn {
  min-height: 34px;
  border-radius: 3px;
  font-weight: 500;
  transition: transform .15s ease, background .18s ease, border-color .18s ease, color .18s ease;
}
.btn:hover, .tb-btn:hover, .q-nav-btn:hover:not(:disabled), .load-q-btn:hover { transform: translateY(-1px); }
.btn:active, .tb-btn:active, .q-nav-btn:active:not(:disabled) { transform: translateY(1px); }
.btn.btn-primary, .tb-btn.tb-btn-primary, .q-nav-btn.primary { background: var(--navy); border-color: var(--navy); }
.btn.btn-primary:hover, .tb-btn.tb-btn-primary:hover, .q-nav-btn.primary:hover:not(:disabled) { background: var(--accent); border-color: var(--accent); }

input, textarea, select, .multi-dd-toggle {
  border-radius: 3px;
  border-color: #cbc8bf;
  background: var(--panel);
  transition: border-color .18s ease, box-shadow .18s ease;
}
input:focus, textarea:focus, select:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(139,38,53,.1); outline: 0; }

/* Reading view: textbook typography and controlled measure. */
.chapter-grid { background: #ebe8e0; }
.chapter-main { background: var(--paper); }
.chapter-hero { background: var(--panel); border: 0; border-top: 4px solid var(--accent); border-bottom: 1px solid var(--line); box-shadow: var(--shadow-small); }
.chapter-toc, .chapter-rail { color: var(--ink); }
.toc-back, .rail-collapse-btn { border-radius: 3px; }

.markdown-body {
  max-width: 76ch;
  font-family: "Source Serif 4", Georgia, serif;
  font-size: 17.5px;
  line-height: 1.72;
  color: #202b3d;
}
.markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4 {
  font-family: "Source Serif 4", Georgia, serif;
  color: var(--navy);
  letter-spacing: -.018em;
}
.markdown-body h2 { border-bottom-color: #c9c5bb; padding-bottom: 9px; }
.markdown-body h3 { font-size: 20px; }
.markdown-body code { font-family: "IBM Plex Mono", monospace; background: #ebe8e0; color: #31425b; }
.markdown-body pre { background: #f7f5ef; border-color: #cbc8bf; border-left: 3px solid var(--navy); }
.markdown-body blockquote { border-left: 3px solid var(--accent); background: #ece8df; color: #465165; }
.markdown-body table th { font-family: "IBM Plex Sans", sans-serif; background: #e9e5dc; }

/* Hosted authentication: asymmetric academic folio. */
.auth-gate {
  min-height: 100dvh;
  height: 100%;
  overflow-y: auto;
  display: grid;
  place-items: center;
  padding: clamp(18px, 4vw, 56px);
  background:
    linear-gradient(90deg, transparent 0 49.92%, rgba(255,255,255,.035) 49.92% 50.08%, transparent 50.08%),
    var(--navy);
}
.auth-gate[hidden] { display: none; }
.auth-frame {
  width: min(1180px, 100%);
  min-height: min(760px, calc(100dvh - 72px));
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(380px, .92fr);
  background: var(--panel);
  box-shadow: 0 35px 90px rgba(4, 12, 25, .3);
}
.auth-intro {
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  padding: clamp(32px, 5vw, 72px);
  background: var(--paper);
  border-right: 1px solid var(--line);
}
.auth-intro::before {
  content: "";
  position: absolute;
  right: -8%;
  top: 14%;
  width: 58%;
  aspect-ratio: 1;
  border: 1px solid rgba(23,36,58,.08);
  border-radius: 50%;
  box-shadow: 0 0 0 42px rgba(23,36,58,.025), 0 0 0 84px rgba(23,36,58,.018);
  pointer-events: none;
}
.auth-intro::after {
  content: "W";
  position: absolute;
  right: -2%;
  bottom: -15%;
  color: rgba(23,36,58,.035);
  font: 600 min(42vw, 32rem)/1 "Source Serif 4", serif;
  pointer-events: none;
}
.auth-brand { position: relative; z-index: 1; display: inline-flex; align-items: center; gap: 13px; width: fit-content; }
.auth-brand-mark {
  width: 43px;
  height: 50px;
  display: grid;
  place-items: center;
  border-radius: 2px 2px 10px 2px;
  background: var(--accent);
  color: #fff;
  font: 600 26px/1 "Source Serif 4", serif;
}
.auth-brand strong { display: block; font: 600 18px/1.1 "Source Serif 4", serif; color: var(--navy); }
.auth-brand small { display: block; margin-top: 4px; color: var(--muted); font-size: 10px; letter-spacing: .08em; text-transform: uppercase; }
.auth-intro-copy { position: relative; z-index: 1; margin-block: auto; padding: 70px 0 54px; max-width: 570px; }
.auth-kicker { color: var(--accent); font-size: 11px; font-weight: 600; letter-spacing: .16em; text-transform: uppercase; }
.auth-intro h1 { margin: 18px 0 24px; max-width: 12ch; font-size: clamp(44px, 5vw, 76px); color: var(--navy); }
.auth-intro-copy > p:last-child { max-width: 49ch; color: #5d687b; font-size: 17px; line-height: 1.7; }
.auth-register { position: relative; z-index: 1; display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin: 0; border-top: 1px solid #c9c5bb; }
.auth-register div { padding: 18px 16px 0 0; }
.auth-register div + div { padding-left: 18px; border-left: 1px solid #c9c5bb; }
.auth-register dt { font: 500 20px/1 "IBM Plex Mono", monospace; color: var(--navy); }
.auth-register dd { margin: 7px 0 0; color: var(--muted); font-size: 11px; line-height: 1.4; }
.auth-provenance { position: relative; z-index: 1; margin: 28px 0 0; max-width: 60ch; color: #7a8290; font-size: 11px; line-height: 1.5; }

.auth-panel { display: flex; flex-direction: column; padding: clamp(30px, 4.5vw, 64px); background: var(--panel); }
.auth-panel-head { display: flex; justify-content: space-between; align-items: center; padding-bottom: 20px; border-bottom: 1px solid var(--line); color: var(--muted); font-size: 10px; letter-spacing: .1em; text-transform: uppercase; }
.auth-status { display: inline-flex; align-items: center; gap: 7px; }
.auth-status i { width: 6px; height: 6px; border-radius: 50%; background: #397052; box-shadow: 0 0 0 3px rgba(57,112,82,.12); }
.auth-panel-copy { margin-top: clamp(48px, 8vh, 90px); max-width: 430px; }
.auth-panel-copy h2 { margin: 6px 0 12px; font-size: clamp(38px, 4vw, 52px); color: var(--navy); font-weight: 600; }
.auth-panel-copy > p:last-child { color: var(--muted); line-height: 1.65; max-width: 43ch; }
.auth-panel #clerk-sign-in { width: 100%; margin-top: 28px; }
.clerk-root, .clerk-card-box { width: 100% !important; }
.clerk-card-box { box-shadow: none !important; }
.clerk-card { width: 100% !important; padding: 0 !important; background: transparent !important; box-shadow: none !important; border: 0 !important; }
.clerk-header { display: none !important; }
.clerk-footer { background: transparent !important; }
.clerk-social-button, .clerk-input { min-height: 44px !important; border: 1px solid #c7c4bb !important; box-shadow: none !important; }
.clerk-social-button:hover { border-color: var(--navy) !important; background: #f5f2eb !important; }
.clerk-primary-button { min-height: 44px !important; background: var(--navy) !important; box-shadow: none !important; font-weight: 500 !important; }
.clerk-primary-button:hover { background: var(--accent) !important; }
.auth-panel-foot { margin-top: auto; padding-top: 30px; border-top: 1px solid var(--line); color: #858b95; font-size: 10px; line-height: 1.55; }
.boot-error { border-top: 4px solid var(--danger); background: var(--panel); box-shadow: var(--shadow); }

@media (prefers-reduced-motion: no-preference) {
  .auth-intro-copy, .auth-register, .auth-panel-copy, #clerk-sign-in {
    animation: academic-enter .55s cubic-bezier(.22,.75,.25,1) both;
  }
  .auth-register { animation-delay: .08s; }
  .auth-panel-copy { animation-delay: .12s; }
  #clerk-sign-in { animation-delay: .18s; }
}
@keyframes academic-enter { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }

@media (max-width: 880px) {
  .auth-gate { padding: 0; place-items: stretch; }
  .auth-frame { min-height: 100dvh; grid-template-columns: 1fr; }
  .auth-intro { padding: 28px 24px 30px; border-right: 0; border-bottom: 1px solid var(--line); }
  .auth-intro-copy { margin: 40px 0 28px; padding: 0; }
  .auth-intro h1 { max-width: 15ch; font-size: clamp(38px, 10vw, 56px); }
  .auth-intro-copy > p:last-child, .auth-provenance { display: none; }
  .auth-register { margin-top: 8px; }
  .auth-panel { padding: 30px 24px 40px; }
  .auth-panel-copy { margin-top: 44px; }
  .auth-panel-foot { margin-top: 48px; }
}

@media (max-width: 560px) {
  .auth-register { grid-template-columns: 1fr; }
  .auth-register div { display: flex; gap: 12px; align-items: baseline; padding: 12px 0; }
  .auth-register div + div { padding-left: 0; border-left: 0; border-top: 1px solid #d5d1c7; }
  .auth-register dd { margin: 0; }
  .auth-panel-head { align-items: flex-start; gap: 20px; }
  .auth-panel-copy h2 { font-size: 40px; }
}

/* Practice workspace — compact, content-led, and independent of stale saved
   rail widths. The paper is the primary surface; navigation and tutor are
   supporting instruments rather than three competing card columns. */
.practice-workspace,
:root[data-toc-collapsed="false"][data-rail-collapsed="false"] .practice-workspace {
  grid-template-columns: clamp(220px, 16vw, 270px) 1px minmax(520px, 1fr) 1px clamp(310px, 22vw, 370px);
  gap: 0;
  padding: 0;
  background: var(--panel);
}

.practice-workspace > .resize-handle { background: var(--line); }
.practice-workspace > .resize-handle::after { display: none; }
.practice-workspace .chapter-toc,
.practice-workspace .chapter-rail {
  border: 0;
  border-radius: 0;
  background: #f0ede5;
}
.practice-workspace .chapter-toc { padding: 18px 16px; }
.practice-workspace .chapter-rail { padding: 18px; }
.practice-workspace .chapter-rail > .rail-collapsible { padding-left: 0; }
.practice-workspace .chapter-main { padding: 0; background: var(--panel); }

.practice-workspace .mock-hero {
  min-height: 0;
  margin: 0;
  padding: 24px 30px 0;
  border-top: 0;
  box-shadow: none;
  background: var(--panel);
}
.practice-workspace .mock-hero h1 { font-size: clamp(38px, 3.2vw, 54px); margin-bottom: 14px; }
.practice-workspace .surface-tabs { margin-top: 4px; padding-top: 0; }
.practice-workspace .surface-tab { padding: 11px 14px; font-size: 13px; }
.practice-workspace .exam-selector {
  margin: 0;
  padding: 14px 30px;
  border-bottom: 1px solid var(--line);
  background: #ece8de;
}
.practice-workspace .exam-chip { border-radius: 3px; padding: 7px 12px; background: transparent; }
.practice-workspace .exam-chip.active { background: var(--navy); border-color: var(--navy); }
.practice-workspace .exam-subtabs { margin: 0; padding: 0 22px; background: var(--panel); }
.practice-workspace .exam-subtab { padding: 12px 14px 10px; font-size: 13px; }
.practice-workspace .pdf-viewer { height: calc(100dvh - 174px); border: 0; border-top: 1px solid var(--line); }

.practice-workspace .chat-panel { gap: 10px; }
.practice-workspace .chat-panel > h4,
.practice-workspace .chat-panel .rail-meta { margin-inline: 2px; }
.practice-workspace .chat-messages { max-height: none; background: var(--panel); border: 0; border-top: 2px solid var(--navy); padding: 16px 2px; }
.practice-workspace .chat-empty { color: var(--muted); font-family: "Source Serif 4", serif; font-size: 15px; line-height: 1.6; }
.practice-workspace .chat-form textarea { background: var(--panel); min-height: 82px; }

.practice-preparing {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 18px;
  align-items: start;
  margin: 28px 30px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.practice-preparing-index { font: 500 12px/1 "IBM Plex Mono", monospace; color: var(--accent); }
.practice-preparing strong { display: block; font: 600 21px/1.15 "Source Serif 4", serif; color: var(--navy); }
.practice-preparing p { margin: 7px 0 0; color: var(--muted); font-size: 13px; }

@media (max-width: 1280px) and (min-width: 821px) {
  .practice-workspace,
  :root[data-toc-collapsed="false"][data-rail-collapsed="false"] .practice-workspace {
    grid-template-columns: 210px 1px minmax(440px, 1fr) 1px 310px;
  }
}