:root {
  --paper: #f4f5f2;
  --surface: #ffffff;
  --surface-raised: #fafbf9;
  --ink: #182223;
  --muted: #687575;
  --line: #d9dfdc;
  --teal: #087d77;
  --teal-soft: #dcefed;
  --coral: #dc684d;
  --coral-soft: #f8e6df;
  --gold: #b6840a;
  --gold-soft: #f5edcf;
  --green: #4e7b52;
  --green-soft: #e2eee2;
  --shadow: 0 12px 30px rgba(20, 42, 40, 0.08);
  --topbar: 64px;
  --library: 320px;
  --splitter: 8px;
  --question-pane: 48%;
  --reading-scale: 1;
  color-scheme: light;
}

body.dark {
  --paper: #151b1b;
  --surface: #1d2525;
  --surface-raised: #222c2b;
  --ink: #ecf1ef;
  --muted: #9caaa7;
  --line: #374442;
  --teal: #56c7bd;
  --teal-soft: #183c39;
  --coral: #ef8e74;
  --coral-soft: #452c27;
  --gold: #d9b950;
  --gold-soft: #3e3822;
  --green: #85b589;
  --green-soft: #263c2a;
  --shadow: none;
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
}
body {
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
  overflow: hidden;
}
button, input, select, textarea { font: inherit; letter-spacing: 0; }
button { color: inherit; }
button:focus-visible, input:focus-visible, select:focus-visible, [tabindex]:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--teal) 32%, transparent);
  outline-offset: 2px;
}

.topbar {
  height: var(--topbar);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 18px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  position: relative;
  z-index: 20;
}
.brand { display: flex; align-items: center; gap: 11px; min-width: 0; margin-right: auto; }
.brand strong { display: block; font-size: 17px; }
.brand small { display: block; color: var(--muted); margin-top: 2px; font-size: 11px; }
.brand-mark {
  width: 38px;
  height: 34px;
  display: flex;
  align-items: end;
  justify-content: center;
  gap: 3px;
  padding: 6px;
  border-radius: 7px;
  background: var(--ink);
}
.brand-mark span { width: 3px; border-radius: 3px 3px 0 0; background: var(--surface); }
.brand-mark span:nth-child(1), .brand-mark span:nth-child(5) { height: 8px; }
.brand-mark span:nth-child(2), .brand-mark span:nth-child(4) { height: 15px; }
.brand-mark span:nth-child(3) { height: 22px; background: var(--coral); }
.topbar-actions, .heading-actions, .toolbar-actions { display: flex; align-items: center; gap: 6px; }

.app-shell {
  display: grid;
  grid-template-columns: var(--library) var(--splitter) minmax(0, 1fr);
  height: calc(100vh - var(--topbar));
  transition: grid-template-columns 160ms ease;
}
.library-pane {
  background: var(--surface);
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding: 14px 12px 0;
  overflow: hidden;
}
.library-pane > .search-wrap,
.library-pane > .filter-row,
.library-pane > .library-summary { flex: 0 0 auto; }
.search-wrap { position: relative; }
.search-wrap input {
  width: 100%;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--surface-raised);
  color: var(--ink);
  padding: 0 38px;
}
.search-icon, .clear-search { position: absolute; top: 50%; transform: translateY(-50%); }
.search-icon { left: 12px; color: var(--muted); width: 18px; height: 18px; }
.clear-search { right: 6px; display: none; }
.search-wrap.has-value .clear-search { display: grid; }
.filter-row {
  display: flex;
  gap: 5px;
  min-height: 32px;
  margin-top: 8px;
  overflow-x: auto;
  overflow-y: hidden;
  scrollbar-width: none;
}
.filter-row::-webkit-scrollbar { display: none; }
.filter-row button, .segmented button {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--muted);
  border-radius: 6px;
  padding: 6px 10px;
  white-space: nowrap;
  cursor: pointer;
}
.filter-row button.active, .segmented button.active {
  color: var(--surface);
  background: var(--ink);
  border-color: var(--ink);
}
.status-filters button { font-size: 12px; padding: 5px 8px; }
.frequency-filters button { font-size: 12px; padding: 5px 8px; }
.library-summary {
  display: flex;
  justify-content: space-between;
  padding: 12px 3px 8px;
  color: var(--muted);
  font-size: 12px;
}
.library-list {
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding-bottom: 16px;
  scrollbar-gutter: stable;
}
.library-item {
  width: 100%;
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr) auto;
  gap: 9px;
  align-items: center;
  padding: 10px 7px;
  border: 0;
  border-top: 1px solid var(--line);
  background: transparent;
  text-align: left;
  cursor: pointer;
}
.library-item:hover { background: var(--surface-raised); }
.library-item.active { background: var(--teal-soft); box-shadow: inset 3px 0 var(--teal); }
.part-label {
  width: 34px;
  height: 30px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 5px;
  font-weight: 700;
  font-size: 12px;
}
.library-item-main { min-width: 0; }
.library-title { font-size: 13px; line-height: 1.35; overflow-wrap: anywhere; }
.library-meta { color: var(--muted); font-size: 11px; margin-top: 4px; }
.status-dot { width: 9px; height: 9px; border-radius: 50%; background: var(--line); }
.status-dot.done { background: var(--green); }
.status-dot.hard { background: var(--coral); }
.status-dot.reviewed { background: var(--gold); }

.study-pane {
  position: relative;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
  overflow: clip;
}
.panel-resizer {
  position: relative;
  z-index: 12;
  width: var(--splitter);
  min-width: var(--splitter);
  cursor: col-resize;
  touch-action: none;
  background: var(--surface-raised);
}
.panel-resizer::after {
  content: "";
  position: absolute;
  inset: 0 3px;
  background: var(--line);
  transition: background 120ms ease, inset 120ms ease;
}
.panel-resizer:hover::after,
.panel-resizer:focus-visible::after,
body.is-resizing .panel-resizer::after {
  inset: 0 2px;
  background: var(--teal);
}
.library-resizer { border-right: 1px solid var(--line); }
body.is-resizing {
  cursor: col-resize;
  user-select: none;
}
body.is-resizing .app-shell,
body.is-resizing .workspace { transition: none; }
.empty-state { height: 100%; display: grid; place-content: center; justify-items: center; text-align: center; }
.empty-state h1 { margin: 18px 0 6px; font-size: 25px; }
.empty-state p { margin: 0; color: var(--muted); }
.empty-visual { display: flex; align-items: center; gap: 6px; height: 92px; }
.empty-visual span { width: 8px; border-radius: 4px; background: var(--ink); }
.empty-visual span:nth-child(1), .empty-visual span:nth-child(7) { height: 24px; }
.empty-visual span:nth-child(2), .empty-visual span:nth-child(6) { height: 47px; background: var(--teal); }
.empty-visual span:nth-child(3), .empty-visual span:nth-child(5) { height: 68px; background: var(--coral); }
.empty-visual span:nth-child(4) { height: 88px; background: var(--gold); }
.study-view { width: 100%; min-width: 0; height: 100%; display: grid; grid-template-rows: auto auto minmax(0, 1fr); }
.study-heading {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 18px;
  padding: 13px 20px 11px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}
.study-heading > div:first-child { flex: 1 1 auto; min-width: 0; }
.study-heading .heading-actions { flex: 0 0 auto; }
.study-heading h1 { margin: 3px 0 0; font-size: 20px; line-height: 1.2; overflow-wrap: anywhere; }
.eyebrow { color: var(--teal); font-size: 10px; font-weight: 800; letter-spacing: 0.09em; }
.audio-dock {
  min-height: 76px;
  display: flex;
  align-items: center;
  gap: 13px;
  padding: 10px 20px;
  background: var(--surface-raised);
  border-bottom: 1px solid var(--line);
}
.play-button {
  flex: 0 0 auto;
  width: 42px;
  height: 42px;
  border: 0;
  border-radius: 50%;
  display: grid;
  place-items: center;
  color: white;
  background: var(--coral);
  cursor: pointer;
}
.audio-main { min-width: 0; flex: 1; }
.wave-track {
  position: relative;
  width: 100%;
  height: 30px;
  overflow: hidden;
  cursor: pointer;
  touch-action: none;
}
.wave-bars { height: 100%; display: flex; align-items: center; gap: 3px; }
.wave-bars span { width: 3px; flex: 1; max-width: 5px; border-radius: 3px; background: var(--line); }
.wave-progress { position: absolute; inset: 0 auto 0 0; width: 0; background: color-mix(in srgb, var(--teal) 18%, transparent); border-right: 2px solid var(--teal); pointer-events: none; }
.audio-meta { display: flex; justify-content: space-between; gap: 12px; margin-top: 3px; color: var(--muted); font-size: 11px; }
#active-caption { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; text-align: right; }
.speed-select { height: 34px; border: 1px solid var(--line); border-radius: 6px; background: var(--surface); color: var(--ink); padding: 0 7px; }

.workspace {
  display: grid;
  grid-template-columns: minmax(280px, var(--question-pane)) var(--splitter) minmax(320px, 1fr);
  min-height: 0;
  transition: grid-template-columns 160ms ease;
}
.question-pane, .transcript-pane { min-height: 0; display: grid; grid-template-rows: auto minmax(0, 1fr) auto; background: var(--surface); }
.question-pane { min-width: 0; }
.pane-toolbar { min-height: 50px; display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 8px 14px; border-bottom: 1px solid var(--line); }
.toolbar-title { display: flex; align-items: baseline; gap: 9px; }
.toolbar-title span { color: var(--muted); font-size: 12px; }
.question-list, .transcript-list { overflow-y: auto; min-height: 0; }
.question-list { padding: 4px 14px 86px; }
.original-question-layout {
  width: 100%;
  overflow-x: auto;
  padding: 6px 0 18px;
  color: var(--ink);
}
.original-question-layout h3,
.original-question-layout h4 {
  margin: 14px 0 8px;
  font-size: 15px;
}
.original-question-layout .group,
.original-question-layout [data-section],
.original-question-layout .notes-section { margin: 0 0 14px; }
.original-question-layout .instructions,
.original-question-layout .instruction {
  color: var(--muted);
  line-height: 1.5;
  font-size: 12px;
}
.original-question-layout table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  font-size: 13px;
}
.original-question-layout th,
.original-question-layout td {
  padding: 10px;
  border: 1px solid var(--line);
  vertical-align: top;
  line-height: 1.6;
  text-align: left;
}
.original-question-layout th { background: var(--surface-raised); }
.original-question-layout .question-number {
  display: inline;
  width: auto;
  height: auto;
  margin: 0;
  border-radius: 0;
  background: transparent;
  color: inherit;
  font: inherit;
}
.original-question-layout label {
  display: block;
  margin: 7px 0;
  line-height: 1.45;
}
.original-question-layout .radio-option {
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr);
  gap: 7px;
  align-items: start;
  margin: 7px 0;
}
.original-question-layout .radio-option label {
  margin: 0;
  cursor: pointer;
}
.original-question-layout .layout-answer-input[type="text"] {
  width: min(170px, 42vw);
  height: 34px;
  margin: 3px 5px;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--surface);
  color: var(--ink);
  padding: 0 8px;
}
.original-question-layout .layout-answer-input[type="radio"] {
  margin-right: 6px;
  accent-color: var(--teal);
}
.original-question-layout select.layout-answer-input {
  min-width: 92px;
  height: 34px;
  margin: 3px 5px;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--surface);
  color: var(--ink);
  padding: 0 8px;
}
.original-question-layout .flowchart-container { margin: 16px 0; }
.original-question-layout .flowchart-title {
  margin-bottom: 9px;
  font-size: 15px;
  font-weight: 800;
}
.original-question-layout .flowchart-step {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr);
  gap: 9px;
  align-items: start;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
}
.original-question-layout .step-number {
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 5px;
  background: var(--ink);
  color: var(--surface);
  font-size: 12px;
  font-weight: 800;
}
.original-question-layout .step-text { line-height: 1.65; }
.original-question-layout .flowchart-pool {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 7px;
  margin: 14px 0 6px;
}
.original-question-layout .flowchart-option {
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--surface-raised);
  line-height: 1.4;
}
.original-question-layout .matching-flex {
  display: grid;
  grid-template-columns: minmax(210px, 1fr) minmax(150px, .68fr);
  gap: 14px;
  align-items: start;
  margin: 12px 0;
}
.original-question-layout .match-list { border-top: 1px solid var(--line); }
.original-question-layout .match-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 76px;
  gap: 8px;
  align-items: center;
  min-height: 48px;
  padding: 7px 0;
  border-bottom: 1px solid var(--line);
}
.original-question-layout .match-q { line-height: 1.45; }
.original-question-layout .matching-options {
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-raised);
}
.original-question-layout .drag-pool {
  display: grid;
  gap: 6px;
  margin-top: 7px;
}
.original-question-layout .drag-option {
  padding: 7px 8px;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--surface);
  line-height: 1.4;
}
.structured-question-layout,
.structured-config-layout { min-width: 0; }
.structured-config-group {
  padding: 14px 0 20px;
  border-bottom: 1px solid var(--line);
}
.structured-config-group > h4 {
  margin: 0 0 5px;
  color: var(--teal);
  font-size: 13px;
  line-height: 1.4;
}
.structured-config-instruction {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}
.structured-single-list .structured-choice-question:first-child { padding-top: 2px; }
.structured-map-figure {
  margin: 12px 0 16px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
}
.structured-map-image {
  display: block;
  width: 100%;
  height: auto;
  object-fit: contain;
}
.structured-map-rows { border-top: 1px solid var(--line); }
.structured-fill-layout { min-width: 0; }
.structured-fill-group { padding: 12px 0 20px; }
.structured-fill-range {
  color: var(--teal);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
}
.structured-fill-instruction {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.5;
}
.structured-fill-title {
  margin: 18px 0 12px;
  font-size: 18px;
  line-height: 1.35;
  text-align: center;
}
.structured-fill-heading {
  margin: 18px 0 7px;
  padding-bottom: 5px;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.4;
}
.structured-note-line {
  display: grid;
  grid-template-columns: 12px minmax(0, 1fr);
  gap: 7px;
  align-items: baseline;
  margin: 6px 0 6px calc(var(--note-level, 0) * 22px);
  line-height: 1.65;
}
.structured-note-line > span { color: var(--muted); }
.structured-inline-answer {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  white-space: nowrap;
  vertical-align: middle;
}
.structured-inline-number {
  color: var(--teal);
  font-size: 11px;
  font-weight: 800;
}
.original-question-layout .structured-inline-answer .layout-answer-input[type="text"] {
  width: min(145px, 34vw);
  margin: 2px 3px;
}
.structured-fill-table-wrap {
  width: 100%;
  margin: 14px 0 4px;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 6px;
}
.structured-fill-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  table-layout: fixed;
  font-size: 13px;
}
.structured-fill-table th,
.structured-fill-table td {
  padding: 10px 11px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  vertical-align: top;
  text-align: left;
  line-height: 1.55;
}
.structured-fill-table th {
  background: var(--surface-raised);
  font-weight: 800;
}
.structured-fill-table tr:last-child > * { border-bottom: 0; }
.structured-fill-table tr > *:last-child { border-right: 0; }
.structured-fill-table-line + .structured-fill-table-line { margin-top: 5px; }
.structured-form-layout { padding: 12px 0 22px; }
.structured-form-title {
  margin: 16px 0 12px;
  font-size: 17px;
  line-height: 1.35;
}
.structured-form-rows { border-top: 1px solid var(--line); }
.original-question-layout .structured-form-row {
  display: grid;
  grid-template-columns: 32px minmax(150px, 1fr) minmax(130px, 190px) auto;
  gap: 9px;
  align-items: center;
  min-height: 58px;
  margin: 0;
  padding: 9px 0;
  border-bottom: 1px solid var(--line);
}
.structured-form-number {
  color: var(--teal);
  font-size: 12px;
  font-weight: 800;
  text-align: center;
}
.structured-form-label,
.structured-form-suffix { line-height: 1.45; }
.structured-form-suffix { color: var(--muted); }
.original-question-layout .structured-form-row .layout-answer-input[type="text"] {
  width: 100%;
  min-width: 0;
  margin: 0;
}
.structured-choice-question,
.structured-choice-group,
.structured-fill-question {
  padding: 14px 0 18px;
  border-bottom: 1px solid var(--line);
}
.structured-question-head {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  margin-bottom: 12px;
  line-height: 1.55;
}
.structured-question-layout .question-number,
.structured-config-layout .question-number {
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  border-radius: 5px;
  background: var(--ink);
  color: var(--surface);
  font-weight: 800;
  font-size: 12px;
}
.structured-option-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}
.original-question-layout .structured-option {
  min-height: 44px;
  display: grid;
  grid-template-columns: 18px 28px minmax(0, 1fr);
  gap: 8px;
  align-items: center;
  margin: 0;
  padding: 9px 11px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
  cursor: pointer;
}
.structured-option:hover { border-color: var(--teal); background: var(--surface-raised); }
.structured-option:has(input:checked) { border-color: var(--teal); background: var(--teal-soft); }
.structured-option input { margin: 0; accent-color: var(--teal); }
.option-letter {
  width: 26px;
  height: 26px;
  display: inline-grid;
  place-items: center;
  border-radius: 5px;
  background: var(--surface-raised);
  border: 1px solid var(--line);
  font-weight: 800;
  font-size: 12px;
}
.structured-option:has(input:checked) .option-letter { background: var(--teal); border-color: var(--teal); color: white; }
.structured-shared-stem { margin: 0 0 12px; line-height: 1.6; font-weight: 700; }
.structured-choice-hint { margin: 9px 0 0; color: var(--muted); font-size: 11px; }
.structured-option-bank {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 6px;
  margin-bottom: 12px;
  padding: 10px;
  background: var(--surface-raised);
  border: 1px solid var(--line);
  border-radius: 6px;
}
.structured-option-bank > div { display: grid; grid-template-columns: 28px minmax(0, 1fr); gap: 7px; align-items: center; }
.structured-match-rows { border-top: 1px solid var(--line); }
.original-question-layout .structured-match-row {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) 76px;
  gap: 10px;
  align-items: center;
  margin: 0;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
}
.structured-match-row select {
  width: 100%;
  height: 36px;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--surface);
  color: var(--ink);
  padding: 0 7px;
}
.structured-text-input { margin-left: 44px !important; }
.original-question-layout .layout-answer-input.is-correct { outline: 2px solid var(--green); }
.original-question-layout .layout-answer-input.is-wrong { outline: 2px solid var(--coral); }
.layout-review {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 6px;
  padding: 10px 0 18px;
}
.layout-review-item {
  min-height: 38px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-raised);
  padding: 6px 9px;
  cursor: pointer;
}
.layout-review-item.correct { border-color: var(--green); }
.layout-review-item.wrong { border-color: var(--coral); }
.layout-review-item span { color: var(--muted); font-size: 11px; }
.question-instructions {
  margin: 8px 0 2px;
  padding: 10px 12px;
  border-left: 3px solid var(--teal);
  background: var(--teal-soft);
  color: var(--muted);
  line-height: 1.5;
  font-size: 12px;
}
.question-instructions strong { color: var(--teal); }
.question-row { padding: 14px 0; border-bottom: 1px solid var(--line); scroll-margin: 78px; }
.question-head { display: grid; grid-template-columns: 34px minmax(0, 1fr) auto; align-items: start; gap: 9px; }
.question-number { width: 30px; height: 30px; display: grid; place-items: center; border-radius: 5px; background: var(--ink); color: var(--surface); font-weight: 800; font-size: 12px; }
.question-row.correct .question-number { background: var(--green); color: white; }
.question-row.wrong .question-number { background: var(--coral); color: white; }
.question-prompt { line-height: 1.55; font-size: 14px; overflow-wrap: anywhere; }
.answer-input {
  width: calc(100% - 43px);
  margin: 9px 0 0 43px;
  height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-raised);
  color: var(--ink);
  padding: 0 11px;
}
.answer-input:disabled { opacity: 0.75; }
.answer-chip {
  border: 1px solid var(--coral);
  background: var(--coral-soft);
  color: var(--coral);
  border-radius: 5px;
  padding: 5px 8px;
  font-weight: 700;
  font-size: 12px;
  cursor: pointer;
}
.analysis-box { display: none; margin: 10px 0 0 43px; padding: 10px 12px; border-left: 3px solid var(--gold); background: var(--gold-soft); line-height: 1.5; font-size: 12px; }
body.show-analysis .analysis-box { display: block; }
.analysis-box strong { color: var(--gold); }
.submit-bar { min-height: 64px; display: flex; align-items: center; justify-content: flex-end; gap: 8px; padding: 10px 14px; border-top: 1px solid var(--line); background: var(--surface); }

.transcript-pane { position: relative; }
.transcript-toolbar { background: var(--surface); }
.segmented { display: flex; }
.segmented button { border-radius: 0; margin-left: -1px; font-size: 12px; }
.segmented button:first-child { border-radius: 6px 0 0 6px; margin-left: 0; }
.segmented button:last-child { border-radius: 0 6px 6px 0; }
.transcript-status { display: none; padding: 7px 14px; background: var(--teal-soft); color: var(--teal); font-size: 12px; }
.transcript-status.visible { display: block; }
.transcript-list { padding: 9px 16px 80px; }
.transcript-line {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 9px;
  width: 100%;
  padding: 8px 7px;
  border: 0;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
  background: transparent;
  text-align: left;
  cursor: pointer;
  scroll-margin: 64px;
}
.transcript-line:hover { background: var(--surface-raised); }
.transcript-line.active { background: var(--teal-soft); box-shadow: inset 3px 0 var(--teal); }
.transcript-line.evidence { box-shadow: inset 3px 0 var(--coral); }
.transcript-time { color: var(--muted); font-size: 11px; padding-top: 3px; }
.transcript-en { display: block; line-height: 1.62; font-family: Georgia, "Times New Roman", serif; font-size: 15px; overflow-wrap: anywhere; cursor: text; user-select: text; -webkit-user-select: text; }
.transcript-zh { display: none; color: var(--muted); line-height: 1.55; margin-top: 6px; font-size: 13px; }
.transcript-line.translated .transcript-zh { display: block; }
.transcript-list.mode-dictation .transcript-en, .transcript-list.mode-dictation .transcript-zh { visibility: hidden; }
.transcript-list.mode-dictation .transcript-line.active .transcript-en { visibility: visible; }
.dictation-placeholder { display: none; color: var(--muted); font-size: 12px; }
.transcript-list.mode-dictation .dictation-placeholder { display: block; }
.sentence-controls { position: absolute; left: 50%; bottom: 14px; transform: translateX(-50%); display: flex; align-items: center; gap: 5px; padding: 5px; border: 1px solid var(--line); border-radius: 7px; background: var(--surface); box-shadow: var(--shadow); }
.lookup-word { pointer-events: none; border-radius: 2px; }
body.word-pick-mode .transcript-line { cursor: default; }
body.word-pick-mode .lookup-word {
  pointer-events: auto;
  cursor: help;
  border-bottom: 1px dotted var(--teal);
}
body.word-pick-mode .lookup-word:hover { background: var(--gold-soft); color: var(--ink); }
body.word-pick-mode .lookup-word.saved { background: var(--teal-soft); color: var(--teal); border-bottom-style: solid; }
.question-prompt,
.original-question-layout { user-select: text; -webkit-user-select: text; }

.icon-button, .clear-search {
  width: 34px;
  height: 34px;
  border: 1px solid transparent;
  border-radius: 6px;
  display: grid;
  place-items: center;
  background: transparent;
  cursor: pointer;
}
.icon-button:hover, .clear-search:hover { background: var(--surface-raised); border-color: var(--line); }
.icon-button.active { background: var(--teal-soft); color: var(--teal); border-color: var(--teal); }
.icon-button svg, .clear-search svg, .text-button svg, .primary-button svg, .secondary-button svg, .danger-button svg { width: 17px; height: 17px; }
.text-button, .primary-button, .secondary-button, .danger-button {
  min-height: 36px;
  border-radius: 6px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 0 12px;
  cursor: pointer;
  font-weight: 700;
}
.text-button, .secondary-button { border: 1px solid var(--line); background: var(--surface); }
.primary-button { border: 1px solid var(--teal); background: var(--teal); color: white; }
.danger-button { border: 1px solid var(--coral); background: var(--coral-soft); color: var(--coral); }
.primary-button:hover { filter: brightness(0.94); }
.secondary-button:hover, .text-button:hover, .danger-button:hover { filter: brightness(0.96); }
button:disabled { opacity: 0.45; cursor: not-allowed; }

dialog {
  width: min(720px, calc(100vw - 28px));
  max-height: min(760px, calc(100vh - 28px));
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--ink);
  box-shadow: 0 28px 80px rgba(10, 26, 25, 0.25);
}
dialog::backdrop { background: rgba(10, 20, 20, 0.48); }
.dialog-heading { position: sticky; top: 0; z-index: 2; display: flex; align-items: center; justify-content: space-between; padding: 17px 20px; border-bottom: 1px solid var(--line); background: var(--surface); }
.dialog-heading h2 { margin: 4px 0 0; font-size: 21px; }
.dialog-heading h2 small { color: var(--muted); font-size: 12px; font-weight: 600; }
.font-dialog { width: min(560px, calc(100vw - 28px)); }
.font-settings { padding: 22px; }
.font-control-row {
  display: grid;
  grid-template-columns: 34px minmax(120px, 1fr) 34px 54px;
  gap: 10px;
  align-items: center;
}
.font-control-row input[type="range"] { width: 100%; accent-color: var(--teal); }
.font-control-row output { color: var(--teal); font-weight: 800; text-align: right; font-variant-numeric: tabular-nums; }
.font-preview {
  display: grid;
  gap: 7px;
  margin: 20px 0;
  padding: 16px;
  border-left: 3px solid var(--teal);
  background: var(--surface-raised);
  line-height: 1.55;
  font-size: calc(15px * var(--reading-scale));
}
.font-preview span { color: var(--muted); font-size: calc(13px * var(--reading-scale)); }
.font-reset { margin-left: auto; }

.vocabulary-dialog { width: min(780px, calc(100vw - 28px)); }
.vocabulary-tools {
  position: sticky;
  top: 77px;
  z-index: 2;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 20px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}
.vocabulary-search {
  position: relative;
  display: grid;
  grid-template-columns: minmax(180px, 1fr) auto;
  flex: 1 1 auto;
  min-width: 0;
}
.vocabulary-search > span { position: absolute; left: 11px; top: 50%; width: 17px; height: 17px; color: var(--muted); transform: translateY(-50%); }
.vocabulary-search > span svg { width: 17px; height: 17px; }
.vocabulary-search input {
  min-width: 0;
  height: 38px;
  padding: 0 11px 0 35px;
  border: 1px solid var(--line);
  border-radius: 6px 0 0 6px;
  background: var(--surface-raised);
  color: var(--ink);
}
.vocabulary-search button { min-height: 38px; margin-left: -1px; border-radius: 0 6px 6px 0; }
.vocabulary-actions { display: flex; gap: 7px; }
.vocabulary-list { max-height: min(570px, calc(100vh - 190px)); overflow-y: auto; padding: 0 20px 20px; }
.vocabulary-entry { padding: 15px 0 12px; border-bottom: 1px solid var(--line); }
.vocabulary-entry-main { display: grid; gap: 7px; width: 100%; padding: 0; border: 0; background: transparent; text-align: left; cursor: pointer; }
.vocabulary-entry-main:hover .vocabulary-word-row strong { color: var(--teal); }
.vocabulary-word-row { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; }
.vocabulary-word-row strong { font-family: Georgia, "Times New Roman", serif; font-size: 20px; }
.vocabulary-word-row time { color: var(--muted); font-size: 11px; }
.vocabulary-definition { line-height: 1.55; font-size: 13px; }
.vocabulary-context {
  display: -webkit-box;
  overflow: hidden;
  color: var(--muted);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 12px;
  line-height: 1.5;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}
.vocabulary-entry-footer { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-top: 10px; color: var(--muted); font-size: 11px; }
.vocabulary-entry-footer > span { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.vocabulary-entry-footer > div { display: flex; flex: 0 0 auto; gap: 3px; }
.vocabulary-delete { color: var(--coral); }

.word-lookup-dialog { width: min(590px, calc(100vw - 28px)); }
.word-lookup-body { padding: 20px; }
.lookup-origin { color: var(--teal); font-size: 12px; font-weight: 700; }
.word-lookup-body blockquote {
  margin: 10px 0 17px;
  padding: 10px 12px;
  border-left: 3px solid var(--line);
  background: var(--surface-raised);
  color: var(--muted);
  font-family: Georgia, "Times New Roman", serif;
  line-height: 1.55;
}
.definition-field { display: grid; gap: 7px; }
.definition-field > span { font-size: 12px; font-weight: 800; }
.definition-field textarea {
  width: 100%;
  resize: vertical;
  min-height: 104px;
  padding: 10px 11px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-raised);
  color: var(--ink);
  line-height: 1.55;
}
.lookup-status { min-height: 19px; margin-top: 7px; color: var(--muted); font-size: 11px; }
.word-lookup-actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 15px; }
.history-stats { display: grid; grid-template-columns: repeat(3, 1fr); border-bottom: 1px solid var(--line); }
.history-stat { padding: 14px 20px; border-right: 1px solid var(--line); }
.history-stat:last-child { border-right: 0; }
.history-stat strong { display: block; font-size: 23px; }
.history-stat span { color: var(--muted); font-size: 11px; }
.history-actions {
  position: sticky;
  top: 77px;
  z-index: 2;
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  padding: 10px 20px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}
.history-actions .danger-button { margin-left: auto; }
.history-list { max-height: 480px; overflow-y: auto; padding: 8px 20px 20px; }
.history-entry { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 12px; padding: 12px 0; border-bottom: 1px solid var(--line); cursor: pointer; }
.history-entry-title { font-weight: 700; font-size: 13px; }
.history-entry-meta { color: var(--muted); margin-top: 4px; font-size: 11px; }
.score { font-weight: 800; color: var(--teal); }
.confirm-dialog { width: min(440px, calc(100vw - 28px)); }
.confirm-dialog-body { padding: 22px; }
.confirm-dialog-body h2 { margin: 0 0 8px; font-size: 20px; }
.confirm-dialog-body p { margin: 0; color: var(--muted); line-height: 1.6; }
.confirm-dialog-actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 22px; }
.toast { position: fixed; left: 50%; bottom: 24px; transform: translate(-50%, 20px); z-index: 100; padding: 9px 13px; border-radius: 6px; background: var(--ink); color: var(--surface); opacity: 0; pointer-events: none; transition: 160ms ease; font-size: 13px; }
.toast.show { opacity: 1; transform: translate(-50%, 0); }
.mobile-only { display: none; }
.empty-list { padding: 30px 10px; text-align: center; color: var(--muted); }

/* Reading controls scale study content while keeping navigation and icon controls stable. */
.question-prompt { font-size: calc(14px * var(--reading-scale)); }
.question-instructions,
.analysis-box,
.original-question-layout .instructions,
.original-question-layout .instruction,
.structured-config-instruction,
.structured-fill-range,
.structured-fill-instruction { font-size: calc(12px * var(--reading-scale)); }
.original-question-layout { font-size: calc(14px * var(--reading-scale)); }
.original-question-layout h3,
.original-question-layout h4,
.original-question-layout .flowchart-title { font-size: calc(15px * var(--reading-scale)); }
.original-question-layout table,
.structured-fill-table,
.structured-config-group > h4 { font-size: calc(13px * var(--reading-scale)); }
.structured-fill-title { font-size: calc(18px * var(--reading-scale)); }
.structured-fill-heading { font-size: calc(14px * var(--reading-scale)); }
.structured-form-title { font-size: calc(17px * var(--reading-scale)); }
.structured-shared-stem { font-size: calc(14px * var(--reading-scale)); }
.transcript-en { font-size: calc(15px * var(--reading-scale)); }
.transcript-zh { font-size: calc(13px * var(--reading-scale)); }
.dictation-placeholder { font-size: calc(12px * var(--reading-scale)); }

@media (max-width: 980px) {
  :root { --library: 288px; }
  .workspace { grid-template-columns: minmax(280px, var(--question-pane)) var(--splitter) minmax(320px, 1fr); }
}

@media (min-width: 761px) {
  body.library-collapsed .app-shell { grid-template-columns: 0 0 minmax(0, 1fr); }
  body.library-collapsed .library-pane,
  body.library-collapsed .library-resizer {
    visibility: hidden;
    pointer-events: none;
    overflow: hidden;
  }
  body.transcript-collapsed .workspace { grid-template-columns: minmax(0, 1fr) 0 0; }
  body.transcript-collapsed .transcript-pane,
  body.transcript-collapsed .workspace-resizer {
    visibility: hidden;
    pointer-events: none;
    overflow: hidden;
  }
}

@media (max-width: 760px) {
  body { overflow: hidden; }
  .mobile-only { display: grid; }
  .topbar { padding: 0 10px; }
  .brand { margin-right: auto; margin-left: 6px; }
  .app-shell { display: block; position: relative; overflow: hidden; overflow: clip; }
  .panel-resizer { display: none; }
  .library-pane {
    position: absolute;
    inset: 0 auto 0 0;
    width: min(88vw, 340px);
    z-index: 30;
    transform: translateX(-101%);
    transition: transform 180ms ease;
    box-shadow: var(--shadow);
    visibility: hidden;
    pointer-events: none;
  }
  body.library-open .library-pane { transform: translateX(0); visibility: visible; pointer-events: auto; }
  .study-pane { height: 100%; }
  .study-heading { padding: 10px 12px; }
  .study-heading h1 { font-size: 17px; }
  .audio-dock { padding: 8px 12px; min-height: 68px; }
  .audio-meta { display: block; }
  #active-caption { display: none; }
  .workspace { display: block; height: 100%; }
  .study-view, .study-heading, .audio-dock, .workspace, .question-pane { width: 100%; min-width: 0; }
  .study-view { grid-template-rows: auto auto minmax(0, 1fr); }
  .question-pane { height: 100%; border-right: 0; }
  .transcript-pane {
    position: absolute;
    inset: 0;
    z-index: 24;
    transform: translateX(101%);
    transition: transform 180ms ease;
    visibility: hidden;
    pointer-events: none;
  }
  body.transcript-open .transcript-pane { transform: translateX(0); visibility: visible; pointer-events: auto; }
  .question-head { grid-template-columns: 32px minmax(0, 1fr) auto; gap: 7px; }
  .answer-input { width: calc(100% - 39px); margin-left: 39px; }
  .analysis-box { margin-left: 39px; }
  .heading-actions .text-button { width: 34px; padding: 0; }
  .heading-actions .text-button span { display: none; }
  .history-stats { grid-template-columns: 1fr; }
  .history-stat { border-right: 0; border-bottom: 1px solid var(--line); }
  .history-actions { top: 77px; padding: 9px 12px; }
  .history-actions .danger-button { margin-left: 0; }
  .vocabulary-tools { top: 77px; display: grid; padding: 9px 12px; }
  .vocabulary-actions { justify-content: stretch; }
  .vocabulary-actions button { flex: 1 1 0; }
  .vocabulary-list { max-height: calc(100vh - 248px); padding: 0 12px 16px; }
  .word-lookup-body { padding: 16px; }
  .word-lookup-actions { flex-wrap: wrap; }
  .structured-option-grid { grid-template-columns: 1fr; }
  .original-question-layout .flowchart-pool { grid-template-columns: 1fr; }
  .original-question-layout .matching-flex { grid-template-columns: 1fr; }
  .original-question-layout .structured-match-row {
    grid-template-columns: 34px minmax(0, 1fr) 68px;
    gap: 7px;
  }
  .original-question-layout .structured-form-row {
    grid-template-columns: 28px minmax(0, 1fr);
    gap: 7px 8px;
    padding: 10px 0;
  }
  .structured-form-number { grid-row: 1 / span 2; }
  .original-question-layout .structured-form-row .layout-answer-input[type="text"] { grid-column: 2; }
  .structured-form-suffix { grid-column: 2; }
}

@media (max-width: 520px) {
  .brand-mark, .brand small { display: none; }
  .brand strong { font-size: 14px; }
  .topbar-actions { gap: 2px; }
  .topbar .icon-button { width: 32px; height: 32px; }
  .font-control-row { grid-template-columns: 34px minmax(90px, 1fr) 34px; }
  .font-control-row output { grid-column: 1 / -1; text-align: center; }
  .vocabulary-entry-footer { align-items: flex-end; }
  .vocabulary-entry-footer > span { white-space: normal; }
}

/* Portfolio demo: source material is original and embedded locally. */