/* ─── Design tokens ─────────────────────────────────────────── */
:root {
  color-scheme: light;
  --ink: #172033;
  --muted: #697386;
  --line: #d7dee9;
  --panel: #ffffff;
  --soft: #eef2f7;
  --soft-2: #f8fafc;
  --accent: #2563a8;
  --accent-dark: #153e75;
  --accent-2: #4d88b8;
  --danger: #c2414b;
  --warn: #b45309;
  --success: #0b7c55;
  --focus: rgba(37, 99, 168, 0.18);
  --shadow: 0 18px 44px rgba(22, 34, 51, 0.1);
  --radius: 8px;
  --sidebar-w: minmax(280px, 340px);
}

/* ─── Dark mode ─────────────────────────────────────────────── */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --ink: #e2e8f5;
    --muted: #7a849a;
    --line: #253046;
    --panel: #141c2e;
    --soft: #1a2438;
    --soft-2: #111827;
    --accent: #5592d8;
    --accent-dark: #a5c4f0;
    --accent-2: #7aabdb;
    --danger: #e56370;
    --warn: #f59e0b;
    --success: #34d399;
    --focus: rgba(85, 146, 216, 0.25);
    --shadow: 0 18px 44px rgba(0, 0, 0, 0.45);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --ink: #e2e8f5;
  --muted: #7a849a;
  --line: #253046;
  --panel: #141c2e;
  --soft: #1a2438;
  --soft-2: #111827;
  --accent: #5592d8;
  --accent-dark: #a5c4f0;
  --accent-2: #7aabdb;
  --danger: #e56370;
  --warn: #f59e0b;
  --success: #34d399;
  --focus: rgba(85, 146, 216, 0.25);
  --shadow: 0 18px 44px rgba(0, 0, 0, 0.45);
}

:root[data-theme="light"] {
  color-scheme: light;
}

/* ─── Reset ─────────────────────────────────────────────────── */
* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background: color-mix(in srgb, var(--soft-2) 60%, var(--soft));
  font: 15px/1.45 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  transition: background 0.25s, color 0.25s;
}

button, input, textarea { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }

button:focus-visible,
a:focus-visible,
input:focus-visible,
textarea:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

/* ─── Layout ─────────────────────────────────────────────────── */
.shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  min-height: 100vh;
}

/* ─── Sidebar ────────────────────────────────────────────────── */
.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  border-right: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 96%, transparent);
  backdrop-filter: blur(18px);
  padding: 14px;
  overflow: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* ─── Brand ──────────────────────────────────────────────────── */
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.mark {
  display: grid;
  place-items: center;
  flex: 0 0 44px;
  width: 44px;
  height: 44px;
  border-radius: var(--radius);
  color: white;
  background: linear-gradient(135deg, #173b69, #2f6fa7);
  box-shadow: 0 6px 18px rgba(23, 59, 105, 0.3);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0;
  flex-shrink: 0;
}

.brandText { flex: 1; min-width: 0; }

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

h1 { font-size: 17px; line-height: 1.1; }
h2 { font-size: clamp(22px, 3vw, 36px); line-height: 1.06; }
h3 { font-size: 17px; }
h4 { font-size: 15px; }

.brand .subtitle { margin-top: 2px; color: #3a6aad; font-size: 11px; font-weight: 800; }
:root[data-theme="dark"] .brand .subtitle,
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .brand .subtitle { color: var(--accent-2); } }
.brand .authors { color: var(--muted); font-size: 10px; line-height: 1.3; margin-top: 1px; }

/* ─── Stats bar ──────────────────────────────────────────────── */
.statsBar {
  display: flex;
  gap: 10px;
  align-items: center;
  padding: 6px 10px;
  border-radius: var(--radius);
  background: var(--soft);
  font-size: 11px;
  color: var(--muted);
  flex-wrap: wrap;
}

.statItem { font-weight: 700; }

/* ─── Search ─────────────────────────────────────────────────── */
.searchBox {
  display: grid;
  gap: 5px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.searchBox input {
  height: 40px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--ink);
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.searchBox input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--focus);
}

.searchBox label span { display: flex; align-items: center; justify-content: space-between; }

kbd {
  display: inline-flex;
  align-items: center;
  padding: 1px 5px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--soft);
  color: var(--muted);
  font-size: 10px;
  font-family: inherit;
}

/* ─── TOC / nav ──────────────────────────────────────────────── */
.topicList {
  display: grid;
  gap: 6px;
  flex: 1;
}

.tocSection {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  overflow: hidden;
}

.tocSection summary {
  min-height: 36px;
  padding: 9px 11px;
  cursor: pointer;
  color: var(--accent-dark);
  font-size: 11px;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--soft);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 6px;
}

.tocSection summary::before { content: "›"; transition: transform 0.15s; }
.tocSection[open] summary::before { transform: rotate(90deg); }

.tocItems,
.tocChildren,
.searchResults {
  display: grid;
  gap: 2px;
  padding: 5px;
}

.tocChildren {
  padding: 0 0 3px 10px;
  border-left: 2px solid var(--line);
  margin-left: 10px;
}

.tocItem { position: relative; }

.tocItem button,
.searchResults button {
  width: 100%;
  min-height: 30px;
  padding: 5px 8px 5px 8px;
  padding-right: 52px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
  font-size: 13px;
  transition: background 0.12s;
  /* prevent long titles from pushing past the badge area */
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tocItem.depth1 button { color: #244a78; font-size: 12px; }
.tocItem.depth2 button { color: var(--muted); font-size: 11px; }

:root[data-theme="dark"] .tocItem.depth1 button { color: var(--accent-2); }

.tocItem button:hover,
.tocItem button.active,
.searchResults button:hover,
.searchResults button.active {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  color: var(--accent-dark);
}

/* Status dot on TOC items */
.tocItem { display: grid; }

.tocItemRow {
  display: flex;
  align-items: center;
  gap: 0;
  position: relative;
}

.tocItemRow button {
  flex: 1;
  padding-right: 48px;
}

.tocBadges {
  position: absolute;
  right: 4px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  align-items: center;
  gap: 2px;
  pointer-events: none;
}

.tocBadges.hasActions { pointer-events: auto; }

.statusDotSmall {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  flex-shrink: 0;
}

.statusDotSmall[data-status="verified"]     { background: var(--success); }
.statusDotSmall[data-status="needs-review"] { background: var(--warn); }
.statusDotSmall[data-status="incorrect"]    { background: var(--danger); }
.statusDotSmall[data-status="unreviewed"]   { display: none; }

.studiedCheck {
  font-size: 11px;
  color: var(--success);
  opacity: 0.85;
}

.bookmarkStar {
  font-size: 12px;
  color: var(--accent);
  cursor: pointer;
  pointer-events: auto;
  padding: 2px;
  border: 0;
  background: transparent;
  opacity: 0;
  transition: opacity 0.15s;
}

.tocItemRow:hover .bookmarkStar { opacity: 1; }
.bookmarkStar.active { opacity: 1; color: #f59e0b; }

.searchResults p {
  padding: 3px 5px 6px;
  color: var(--muted);
  font-size: 11px;
}

/* ─── Bookmarks section ──────────────────────────────────────── */
.bookmarkSection { }
.tocSection.bookmarks summary { background: color-mix(in srgb, #f59e0b 12%, var(--soft)); }

/* ─── Recent section ─────────────────────────────────────────── */
.recentSection summary { background: var(--soft); color: var(--muted); }
.recentSection { margin-top: auto; }

/* ─── Workspace ──────────────────────────────────────────────── */
.workspace {
  display: grid;
  gap: 16px;
  padding: 18px;
  min-width: 0;
  align-content: start;
}

.workspacePanel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.workspaceHeader,
.tabHeader {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
}

.workspaceActions {
  display: flex;
  gap: 6px;
  align-items: center;
  flex-wrap: wrap;
}

/* ─── Status selector ────────────────────────────────────────── */
.statusSelector { position: relative; }

.statusBtn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 34px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--soft-2);
  color: var(--ink);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
}

.statusBtn .statusDot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--muted);
  flex-shrink: 0;
}

.statusBtn[data-status="verified"]     .statusDot { background: var(--success); }
.statusBtn[data-status="needs-review"] .statusDot { background: var(--warn); }
.statusBtn[data-status="incorrect"]    .statusDot { background: var(--danger); }

.statusMenu {
  position: absolute;
  top: calc(100% + 4px);
  right: 0;
  z-index: 100;
  min-width: 160px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 4px;
  display: grid;
  gap: 2px;
}

.statusMenu button {
  width: 100%;
  min-height: 32px;
  padding: 6px 10px;
  border: 0;
  border-radius: 5px;
  background: transparent;
  color: var(--ink);
  text-align: left;
  font-size: 13px;
  cursor: pointer;
}

.statusMenu button:hover { background: var(--soft); }

/* ─── Buttons ────────────────────────────────────────────────── */
.formActions button,
.tabHeader button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 36px;
  padding: 0 13px;
  border: 0;
  border-radius: 6px;
  background: var(--accent);
  color: white;
  font-weight: 800;
  cursor: pointer;
}

.ghostBtn {
  min-height: 34px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--soft);
  color: var(--accent-dark);
  font-weight: 800;
  cursor: pointer;
  font-size: 13px;
}

.iconBtn {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--soft-2);
  color: var(--muted);
  cursor: pointer;
  font-size: 15px;
  padding: 0;
}

.iconBtn:hover { background: var(--soft); color: var(--ink); }

.studiedBtn {
  min-height: 34px;
  padding: 0 11px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--soft-2);
  color: var(--ink);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
}

.studiedBtn.done {
  background: color-mix(in srgb, var(--success) 14%, var(--soft-2));
  border-color: color-mix(in srgb, var(--success) 40%, var(--line));
  color: var(--success);
}

/* ─── Tabs ───────────────────────────────────────────────────── */
.workspaceTabs {
  display: flex;
  gap: 4px;
  padding: 7px 10px;
  border-bottom: 1px solid var(--line);
  background: var(--soft-2);
}

.workspaceTabs button {
  min-height: 34px;
  border: 0;
  border-radius: 6px;
  padding: 0 13px;
  background: transparent;
  color: var(--muted);
  font-weight: 800;
  cursor: pointer;
  font-size: 13px;
}

.workspaceTabs button.active {
  background: var(--panel);
  color: var(--accent-dark);
  box-shadow: inset 0 0 0 1px var(--line);
}

.tabPane { display: none; }
.tabPane.active { display: block; }

/* ─── Iframe ─────────────────────────────────────────────────── */
iframe {
  display: block;
  width: 100%;
  height: min(74vh, 840px);
  min-height: 560px;
  border: 0;
  background: white;
}

/* ─── Retrieve form ──────────────────────────────────────────── */
.questionForm {
  display: grid;
  gap: 10px;
  padding: 14px;
  border-bottom: 1px solid var(--line);
}

textarea {
  width: 100%;
  resize: vertical;
  min-height: 88px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--soft-2);
  color: var(--ink);
  outline: none;
}

textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--focus);
}

.formActions {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
}

.toggle {
  display: flex;
  align-items: center;
  gap: 7px;
  color: var(--muted);
  font-size: 13px;
  cursor: pointer;
}

/* ─── Answer panel ───────────────────────────────────────────── */
.answerPanel {
  padding: 14px;
  border-bottom: 1px solid var(--line);
}

.answerPanel:empty { display: none; }
.answerPanel h4 { margin-bottom: 7px; }

.answerPanel ul { margin: 8px 0 0 16px; padding: 0; }
.answerPanel li { margin: 6px 0; }

.answerPanel li button {
  margin-left: 4px;
  border: 0;
  padding: 2px 7px;
  border-radius: 5px;
  background: var(--soft);
  color: var(--accent-dark);
  font-weight: 800;
  cursor: pointer;
}

/* ─── Result list ────────────────────────────────────────────── */
.resultsList {
  display: grid;
  gap: 8px;
  max-height: 560px;
  overflow: auto;
  padding: 10px;
}

.result {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 11px;
  background: var(--soft-2);
}

.resultTitle {
  display: block;
  width: 100%;
  border: 0;
  padding: 0;
  background: transparent;
  color: var(--accent-dark);
  font-weight: 900;
  text-align: left;
  cursor: pointer;
  font-size: 14px;
}

.resultText { margin-top: 7px; font-size: 13px; line-height: 1.5; }

.resultTags {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  margin-top: 8px;
}

.resultTags span {
  padding: 2px 7px;
  border-radius: 999px;
  background: var(--soft);
  color: var(--accent-dark);
  font-size: 11px;
}

/* ─── MCQ / questions ────────────────────────────────────────── */
.mcqOutput {
  padding: 14px;
  max-height: 680px;
  overflow: auto;
}

.mcq, .topicQuestions {
  display: grid;
  gap: 10px;
  margin-top: 10px;
}

.topicQuestion, .mcq article {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px;
  background: var(--soft-2);
}

.topicQuestion > button {
  min-height: 32px;
  margin-top: 9px;
  border: 0;
  border-radius: 6px;
  padding: 0 11px;
  background: var(--soft);
  color: var(--accent-dark);
  font-weight: 800;
  cursor: pointer;
}

.hiddenAnswer {
  margin-top: 10px;
  padding: 9px 12px;
  border-left: 3px solid var(--accent-2);
  border-radius: 6px;
  background: var(--panel);
}

.hiddenAnswer p, .hiddenAnswer ul { margin: 0; }
.hiddenAnswer ul { padding-left: 16px; }

.mcq button {
  display: block;
  width: 100%;
  min-height: 34px;
  margin-top: 6px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel);
  color: var(--ink);
  text-align: left;
  padding: 0 10px;
  cursor: pointer;
  font-size: 13px;
  transition: background 0.12s, border-color 0.12s;
}

.mcq button:hover { background: var(--soft); }
.mcq button.correct  { border-color: var(--success); background: color-mix(in srgb, var(--success) 12%, var(--panel)); color: var(--success); }
.mcq button.incorrect { border-color: var(--danger); background: color-mix(in srgb, var(--danger) 10%, var(--panel)); color: var(--danger); }

/* ─── Typography helpers ─────────────────────────────────────── */
.eyebrow {
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 800;
  font-size: 11px;
  color: var(--muted);
}

.brand p, .eyebrow, .resultMeta, .resultTags, .answerNote, .empty {
  color: var(--muted);
  font-size: 12px;
}

.empty { padding: 10px 0; }

mark {
  background: color-mix(in srgb, var(--accent) 18%, transparent);
  color: var(--accent-dark);
  padding: 0 2px;
  border-radius: 2px;
}

/* ─── Shortcut hint overlay ──────────────────────────────────── */
.shortcutHint {
  position: fixed;
  bottom: 18px;
  right: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 12px 16px;
  font-size: 12px;
  z-index: 200;
}

.shortcutGrid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 6px 12px;
  align-items: center;
}

/* ─── Responsive ─────────────────────────────────────────────── */
@media (max-width: 1100px) {
  .shell { grid-template-columns: 1fr; }
  .sidebar { position: static; height: auto; max-height: 480px; }
}

@media (max-width: 640px) {
  .workspace, .sidebar { padding: 12px; }
  .workspaceHeader, .tabHeader, .formActions { align-items: stretch; flex-direction: column; }
  .workspaceActions, .workspaceActions button, .formActions button { width: 100%; }
  .workspaceTabs { overflow-x: auto; }
  iframe { min-height: 440px; }
}