/* ============================================================
   Arithmetic Master — Stylesheet
   Modern, responsive, dark/light themed UI
   ============================================================ */

:root {
  --bg: #f4f6fb;
  --bg-elev: #ffffff;
  --text: #1a2030;
  --text-muted: #5b6478;
  --primary: #4f46e5;
  --primary-600: #4338ca;
  --primary-50: #eef2ff;
  --accent: #06b6d4;
  --ok: #10b981;
  --bad: #ef4444;
  --warn: #f59e0b;
  --border: #e5e7eb;
  --border-strong: #d1d5db;
  --chip-bg: #eef2ff;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .06);
  --shadow: 0 8px 30px rgba(15, 23, 42, .08);
  --radius: 14px;
  --radius-sm: 10px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

[data-theme="dark"] {
  --bg: #0b1020;
  --bg-elev: #141b2e;
  --text: #e6e9f2;
  --text-muted: #8c95ad;
  --primary: #818cf8;
  --primary-600: #6366f1;
  --primary-50: #1e1b4b;
  --accent: #22d3ee;
  --border: #232a44;
  --border-strong: #2e375a;
  --chip-bg: #1c2440;
  --shadow: 0 8px 30px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* =============== Topbar =============== */
.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: #fff;
  box-shadow: var(--shadow-sm);
}
.brand { display: flex; align-items: center; gap: 14px; }
.logo {
  font-size: 36px;
  background: rgba(255, 255, 255, .15);
  width: 56px; height: 56px;
  display: grid; place-items: center;
  border-radius: 14px;
  backdrop-filter: blur(8px);
}
.brand h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -.02em;
}
.tagline {
  margin: 2px 0 0;
  font-size: 13px;
  opacity: .85;
}
.topbar-actions { display: flex; gap: 8px; }
.icon-btn {
  width: 40px; height: 40px;
  border: 0;
  background: rgba(255, 255, 255, .15);
  color: #fff;
  border-radius: 10px;
  font-size: 18px;
  cursor: pointer;
  transition: background .15s;
}
.icon-btn:hover { background: rgba(255, 255, 255, .28); }

/* =============== Layout =============== */
#app {
  max-width: 1080px;
  margin: 28px auto;
  padding: 0 20px 60px;
}

.screen { display: none; animation: fade .25s ease; }
.screen.active { display: block; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
}
.card h2 { margin: 0 0 6px; font-size: 22px; }
.card h3 { margin: 28px 0 12px; font-size: 16px; color: var(--text-muted); text-transform: uppercase; letter-spacing: .08em; }

.muted { color: var(--text-muted); }
.muted.small { font-size: 13px; margin: 6px 0 12px; }

/* =============== Form Elements =============== */
.field { margin-top: 22px; }
.field > label {
  display: block;
  font-weight: 600;
  margin-bottom: 10px;
  font-size: 14px;
}
label.small { font-size: 12px; color: var(--text-muted); font-weight: 500; }

input[type="text"],
input[type="number"],
select,
textarea {
  width: 100%;
  padding: 11px 14px;
  background: var(--bg);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 15px;
  font-family: var(--font);
  transition: border-color .15s, box-shadow .15s;
}
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, .15);
}
textarea { font-family: var(--mono); resize: vertical; }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-top: 8px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 8px; }
@media (max-width: 720px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
}

.row { display: flex; align-items: center; gap: 8px; }
.row input { flex: 1; }
.dash { color: var(--text-muted); font-weight: 600; }

/* =============== Op Pills & Mode Tabs =============== */
.op-pills, .mode-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.op-pill, .mode-tab {
  padding: 10px 16px;
  border: 1px solid var(--border-strong);
  background: var(--bg);
  color: var(--text);
  border-radius: 999px;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  transition: all .15s;
}
.mode-tab { border-radius: var(--radius-sm); }
.op-pill:hover, .mode-tab:hover { border-color: var(--primary); color: var(--primary); }
.op-pill.active, .mode-tab.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.mode-panel { display: none; padding-top: 14px; }
.mode-panel.active { display: block; }

/* =============== Switch =============== */
.switch {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  margin-top: 4px;
}
.switch input { display: none; }
.slider {
  width: 38px; height: 22px;
  background: var(--border-strong);
  border-radius: 999px;
  position: relative;
  transition: background .2s;
}
.slider::after {
  content: '';
  position: absolute;
  width: 18px; height: 18px;
  background: #fff;
  border-radius: 50%;
  top: 2px; left: 2px;
  transition: transform .2s;
  box-shadow: 0 1px 3px rgba(0,0,0,.3);
}
.switch input:checked + .slider { background: var(--primary); }
.switch input:checked + .slider::after { transform: translateX(16px); }
.switch-label { font-size: 13px; color: var(--text); }

/* =============== Buttons =============== */
.actions {
  display: flex;
  gap: 10px;
  margin-top: 28px;
  flex-wrap: wrap;
}
.btn {
  padding: 11px 20px;
  border: 1px solid var(--border-strong);
  background: var(--bg-elev);
  color: var(--text);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  font-family: var(--font);
  transition: all .15s;
}
.btn:hover { border-color: var(--primary); color: var(--primary); }
.btn.primary {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}
.btn.primary:hover { background: var(--primary-600); border-color: var(--primary-600); color: #fff; }
.btn.ghost { background: transparent; }
.btn.big { padding: 14px 28px; font-size: 16px; }
.btn.small { padding: 8px 14px; font-size: 13px; }

/* =============== Quiz Screen =============== */
.quiz-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  margin-bottom: 18px;
  flex-wrap: wrap;
}
.progress-wrap { flex: 1; min-width: 200px; }
.progress-bar {
  height: 8px;
  background: var(--border);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 6px;
}
#progressFill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 999px;
  transition: width .25s;
}
.quiz-stats { display: flex; gap: 8px; }
.chip {
  background: var(--chip-bg);
  color: var(--text);
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
}
.chip.ok { background: rgba(16, 185, 129, .15); color: var(--ok); }
.chip.bad { background: rgba(239, 68, 68, .15); color: var(--bad); }
.quiz-actions { display: flex; gap: 6px; }

.quiz-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 56px 32px;
  box-shadow: var(--shadow);
  text-align: center;
}
.question {
  font-size: clamp(48px, 9vw, 84px);
  font-weight: 800;
  letter-spacing: -.02em;
  margin-bottom: 32px;
  font-family: var(--mono);
  color: var(--text);
  word-break: break-word;
}
#answerForm {
  display: flex;
  gap: 10px;
  max-width: 480px;
  margin: 0 auto;
}
#answerInput {
  flex: 1;
  font-size: 22px;
  padding: 14px 18px;
  text-align: center;
  font-family: var(--mono);
}
.feedback {
  margin-top: 22px;
  min-height: 32px;
  font-weight: 600;
  font-size: 18px;
  transition: opacity .2s;
}
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--bad); }
.feedback .correct-answer {
  display: inline-block;
  background: rgba(239, 68, 68, .12);
  padding: 4px 12px;
  border-radius: 8px;
  margin-left: 6px;
  font-family: var(--mono);
}

/* =============== Results =============== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin: 20px 0 30px;
}
@media (max-width: 720px) {
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}
.stat {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px 18px;
}
.stat-label { font-size: 12px; color: var(--text-muted); text-transform: uppercase; letter-spacing: .08em; }
.stat-value { font-size: 28px; font-weight: 800; margin: 4px 0; font-family: var(--mono); }
.stat-sub { font-size: 12px; color: var(--text-muted); }

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  max-height: 380px;
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
thead {
  background: var(--bg);
  position: sticky;
  top: 0;
}
th, td {
  padding: 10px 14px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
th { font-weight: 600; color: var(--text-muted); font-size: 12px; text-transform: uppercase; letter-spacing: .06em; }
tbody tr:hover { background: var(--primary-50); }
td.q { font-family: var(--mono); }
.badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}
.badge.ok { background: rgba(16, 185, 129, .15); color: var(--ok); }
.badge.bad { background: rgba(239, 68, 68, .15); color: var(--bad); }
.badge.slow { background: rgba(245, 158, 11, .15); color: var(--warn); }

.ai-insight {
  margin-top: 22px;
  padding: 18px 20px;
  background: linear-gradient(135deg, rgba(79, 70, 229, .08), rgba(6, 182, 212, .08));
  border: 1px solid var(--primary);
  border-radius: var(--radius-sm);
  font-size: 14px;
}
.ai-insight strong { color: var(--primary); }
.ai-insight ul { margin: 8px 0 0; padding-left: 22px; }

/* =============== Modal =============== */
/* Fix: ensure [hidden] always wins over .modal display rule */
[hidden] { display: none !important; }

.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 20px;
  animation: fade .2s ease;
}
.modal-content {
  max-width: 720px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  position: relative;
}
.close-btn {
  position: absolute;
  top: 16px; right: 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  width: 36px; height: 36px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 16px;
  color: var(--text);
}
.help-list li { margin-bottom: 10px; line-height: 1.55; }
code, kbd {
  background: var(--chip-bg);
  padding: 2px 7px;
  border-radius: 6px;
  font-family: var(--mono);
  font-size: 90%;
}
kbd { border: 1px solid var(--border-strong); }

/* =============== Toast =============== */
.toast {
  position: fixed;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--text);
  color: var(--bg-elev);
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 500;
  box-shadow: var(--shadow);
  z-index: 200;
  opacity: 0;
  transition: opacity .25s, transform .25s;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* =============== Footer =============== */
.footer {
  text-align: center;
  padding: 24px 20px 40px;
  font-size: 13px;
  color: var(--text-muted);
}

/* =============== App Mode Tabs (Arithmetic / Essay) =============== */
.app-modes {
  display: flex;
  gap: 8px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  padding: 6px;
  border-radius: 999px;
  margin-bottom: 24px;
  width: fit-content;
  box-shadow: var(--shadow-sm);
}
.app-mode {
  padding: 10px 22px;
  border: 0;
  background: transparent;
  color: var(--text-muted);
  border-radius: 999px;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  font-family: var(--font);
  transition: all .15s;
}
.app-mode:hover { color: var(--primary); }
.app-mode.active {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
}

/* =============== Essay: Source Tabs =============== */
.source-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 14px;
  border-bottom: 2px solid var(--border);
}
.source-tab {
  padding: 10px 16px;
  border: 0;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  font-family: var(--font);
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all .15s;
}
.source-tab:hover { color: var(--primary); }
.source-tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}
.source-panel { display: none; padding-top: 12px; }
.source-panel.active { display: block; }

/* =============== Essay: File Upload Areas =============== */
.upload-area {
  border: 2px dashed var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 28px;
  text-align: center;
  cursor: pointer;
  transition: all .15s;
  background: var(--bg);
}
.upload-area:hover {
  border-color: var(--primary);
  background: var(--primary-50);
}
.upload-area.dragover {
  border-color: var(--primary);
  background: var(--primary-50);
}
.upload-area .upload-icon { font-size: 40px; margin-bottom: 8px; }
.upload-area .upload-hint { color: var(--text-muted); font-size: 13px; margin-top: 6px; }
.upload-area input[type="file"] { display: none; }

.format-hint {
  background: var(--bg);
  border-left: 3px solid var(--accent);
  padding: 10px 14px;
  border-radius: 6px;
  margin-top: 10px;
  font-size: 13px;
  color: var(--text-muted);
}
.format-hint code {
  display: inline-block;
  margin: 2px 4px;
}

/* =============== Essay: Manual Input =============== */
.qa-pair {
  display: grid;
  grid-template-columns: auto 1fr 1fr auto;
  gap: 8px;
  align-items: center;
  margin-bottom: 8px;
}
.qa-pair .qa-num {
  font-family: var(--mono);
  font-weight: 700;
  color: var(--text-muted);
  background: var(--bg);
  padding: 8px 12px;
  border-radius: 6px;
  min-width: 36px;
  text-align: center;
}
.qa-pair input { padding: 10px 12px; }
.qa-pair .delete-btn {
  background: transparent;
  border: 1px solid var(--border-strong);
  color: var(--bad);
  width: 36px; height: 36px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 16px;
  transition: all .15s;
}
.qa-pair .delete-btn:hover { background: rgba(239, 68, 68, .12); border-color: var(--bad); }

/* =============== Essay: Question List Preview =============== */
.question-list {
  margin-top: 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  max-height: 280px;
  overflow-y: auto;
}
.question-list-header {
  padding: 10px 14px;
  background: var(--chip-bg);
  font-size: 13px;
  font-weight: 600;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.question-item {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 14px;
}
.question-item:last-child { border-bottom: 0; }
.question-item .q-num {
  font-family: var(--mono);
  color: var(--text-muted);
  font-weight: 700;
  min-width: 30px;
}
.question-item .q-text {
  flex: 1;
  word-break: break-word;
  white-space: pre-wrap;
}
.question-item .q-text small {
  display: block;
  color: var(--text-muted);
  margin-top: 4px;
}
.question-item img {
  max-height: 60px;
  max-width: 80px;
  border-radius: 6px;
  border: 1px solid var(--border);
  object-fit: cover;
}

/* =============== Essay: Practice (Typed) Screen =============== */
.essay-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow);
}
.essay-question {
  font-size: var(--essay-font-size, 22px);
  line-height: 1.5;
  margin-bottom: 24px;
  padding: 20px;
  background: var(--bg);
  border-left: 4px solid var(--primary);
  border-radius: 8px;
  white-space: pre-wrap;
}
.essay-question img {
  max-width: 100%;
  max-height: 400px;
  border-radius: 8px;
  display: block;
  margin: 8px auto;
}
.essay-answer-area {
  width: 100%;
  min-height: 140px;
  padding: 14px 16px;
  font-size: var(--essay-font-size, 18px);
  line-height: 1.5;
  font-family: var(--font);
}
.essay-actions {
  display: flex;
  gap: 10px;
  margin-top: 16px;
  flex-wrap: wrap;
}
.essay-tts-controls {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-top: 12px;
  flex-wrap: wrap;
}
.essay-tts-controls label { font-size: 13px; color: var(--text-muted); }
.essay-tts-controls input[type="range"] {
  width: 120px;
  background: transparent;
  cursor: pointer;
}
.tts-btn {
  background: var(--accent);
  color: #fff;
  border: 0;
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  font-size: 13px;
}
.tts-btn:hover { opacity: .9; }

/* =============== Essay: Diff Highlighting =============== */
.diff-result {
  margin-top: 18px;
  padding: 18px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: var(--essay-font-size, 16px);
  line-height: 1.7;
}
.diff-result h4 {
  margin: 0 0 8px;
  font-size: 13px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: .06em;
}
.diff-section { margin-bottom: 14px; }
.diff-section:last-child { margin-bottom: 0; }
.diff-word {
  display: inline-block;
  padding: 1px 4px;
  border-radius: 4px;
  margin: 1px;
}
.diff-match { background: rgba(16, 185, 129, .15); color: var(--ok); }
.diff-extra { background: rgba(239, 68, 68, .15); color: var(--bad); text-decoration: line-through; }
.diff-missing { background: rgba(245, 158, 11, .18); color: var(--warn); border-bottom: 2px dashed var(--warn); }
.diff-legend {
  display: flex;
  gap: 14px;
  font-size: 12px;
  margin-top: 12px;
  color: var(--text-muted);
  flex-wrap: wrap;
}
.diff-legend span { display: inline-flex; align-items: center; gap: 4px; }
.diff-legend .swatch {
  width: 14px; height: 14px; border-radius: 3px; display: inline-block;
}

/* =============== Essay: Flashcard =============== */
.flashcard-wrap {
  perspective: 1200px;
  margin: 0 auto;
  max-width: 720px;
}
.flashcard {
  position: relative;
  width: 100%;
  min-height: 360px;
  transform-style: preserve-3d;
  transition: transform .6s;
  cursor: pointer;
}
.flashcard.flipped { transform: rotateY(180deg); }
.flashcard-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  font-size: var(--essay-font-size, 28px);
  line-height: 1.5;
  white-space: pre-wrap;
}
.flashcard-face.back {
  transform: rotateY(180deg);
  background: linear-gradient(135deg, var(--primary-50), var(--bg-elev));
  border-color: var(--primary);
}
.flashcard-face .face-label {
  position: absolute;
  top: 12px; left: 16px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--text-muted);
  font-weight: 600;
}
.flashcard-face img {
  max-width: 100%;
  max-height: 320px;
  border-radius: 8px;
  object-fit: contain;
}
.flashcard-controls {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-top: 22px;
  flex-wrap: wrap;
}
.flashcard-controls .nav-btn {
  width: 48px; height: 48px;
  border-radius: 50%;
  border: 1px solid var(--border-strong);
  background: var(--bg-elev);
  color: var(--text);
  font-size: 18px;
  cursor: pointer;
  font-weight: 700;
}
.flashcard-controls .nav-btn:hover { background: var(--primary); color: #fff; border-color: var(--primary); }
.flashcard-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 10px;
}
.flashcard-info {
  font-weight: 600;
  font-size: 15px;
  color: var(--text-muted);
}

/* =============== Essay: Font Size Slider =============== */
.font-control {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  color: var(--text-muted);
}
.font-control input[type="range"] {
  width: 120px;
}

/* Toggle group (Practice/Flashcard mode pick) */
.toggle-group {
  display: flex;
  gap: 6px;
  background: var(--bg);
  padding: 4px;
  border-radius: 999px;
  border: 1px solid var(--border);
  width: fit-content;
}
.toggle-group button {
  padding: 8px 18px;
  border: 0;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-weight: 600;
  font-size: 13px;
  border-radius: 999px;
  font-family: var(--font);
}
.toggle-group button.active {
  background: var(--primary);
  color: #fff;
}

/* =============== Help Modal Tabs =============== */
.help-tabs {
  display: flex;
  gap: 4px;
  margin: 16px 0;
  border-bottom: 2px solid var(--border);
}
.help-tab {
  padding: 10px 18px;
  border: 0;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-weight: 600;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  font-size: 14px;
  font-family: var(--font);
}
.help-tab.active { color: var(--primary); border-bottom-color: var(--primary); }
.help-section { display: none; }
.help-section.active { display: block; }

/* =============== MCQ Practice =============== */
.mcq-form {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px;
}
.mcq-form-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 14px;
  align-items: center;
  margin-bottom: 12px;
}
@media (max-width: 720px) {
  .mcq-form-row { grid-template-columns: 1fr; }
}
.mcq-id-input {
  font-family: var(--mono);
  font-weight: 600;
}
.mcq-options-edit {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 14px 0;
}
.mcq-option-edit {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 10px;
  align-items: center;
  padding: 8px 12px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color .15s, background .15s;
}
.mcq-option-edit:hover { border-color: var(--primary); }
.mcq-option-edit.is-correct {
  background: rgba(16, 185, 129, .08);
  border-color: var(--ok);
}
.mcq-option-edit .opt-letter {
  font-weight: 700;
  font-family: var(--mono);
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: var(--chip-bg);
  color: var(--text);
}
.mcq-option-edit input[type="text"] {
  border: 0;
  background: transparent;
  padding: 8px 0;
}
.mcq-option-edit input[type="text"]:focus {
  outline: none;
  box-shadow: none;
}
.mcq-option-edit .correct-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  user-select: none;
  padding: 4px 8px;
  border-radius: 6px;
}
.mcq-option-edit .correct-toggle input {
  margin: 0;
  cursor: pointer;
}
.mcq-option-edit.is-correct .correct-toggle { color: var(--ok); }

.mcq-form-actions {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
  margin-top: 12px;
}

/* MCQ Question List Items */
.mcq-question-item {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 12px;
  align-items: center;
  font-size: 14px;
  position: relative;
  transition: background .15s;
}
.mcq-question-item:last-child { border-bottom: 0; }
.mcq-question-item:hover { background: var(--primary-50); }
.mcq-question-item .mcq-mini-id {
  font-family: var(--mono);
  font-weight: 700;
  color: var(--primary);
  background: var(--chip-bg);
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
  white-space: nowrap;
}
.mcq-question-item .mcq-mini-text {
  word-break: break-word;
}
.mcq-question-item .mcq-mini-text small {
  display: block;
  color: var(--text-muted);
  margin-top: 4px;
  font-size: 12px;
}
.mcq-question-item .mcq-multi-tag {
  display: inline-block;
  padding: 1px 8px;
  border-radius: 999px;
  background: rgba(245, 158, 11, .15);
  color: var(--warn);
  font-size: 11px;
  font-weight: 600;
  margin-left: 6px;
}
.mcq-question-item .delete-btn {
  background: transparent;
  border: 1px solid var(--border-strong);
  color: var(--bad);
  width: 32px; height: 32px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  opacity: 0;
  transition: opacity .15s, background .15s;
}
.mcq-question-item:hover .delete-btn { opacity: 1; }
.mcq-question-item .delete-btn:hover {
  background: rgba(239, 68, 68, .12);
  border-color: var(--bad);
}

/* MCQ Quiz View */
.mcq-id-badge {
  display: inline-block;
  padding: 4px 12px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  border-radius: 999px;
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 700;
  margin-bottom: 12px;
}
.mcq-question-text {
  font-size: 22px;
  line-height: 1.5;
  margin-bottom: 24px;
  padding: 18px 20px;
  background: var(--bg);
  border-left: 4px solid var(--primary);
  border-radius: 8px;
  white-space: pre-wrap;
  word-break: break-word;
}
.mcq-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 18px;
}
.mcq-option {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  background: var(--bg);
  border: 2px solid var(--border-strong);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 16px;
  transition: all .15s;
  position: relative;
}
.mcq-option:hover:not(.disabled) {
  border-color: var(--primary);
  background: var(--primary-50);
}
.mcq-option input { margin: 0; cursor: pointer; transform: scale(1.2); }
.mcq-option .opt-letter {
  font-weight: 700;
  font-family: var(--mono);
  background: var(--chip-bg);
  color: var(--text);
  width: 32px; height: 32px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  flex-shrink: 0;
}
.mcq-option .opt-text { flex: 1; word-break: break-word; }
.mcq-option.checked {
  border-color: var(--primary);
  background: var(--primary-50);
}
.mcq-option.disabled { cursor: default; }
.mcq-option.show-correct {
  border-color: var(--ok);
  background: rgba(16, 185, 129, .12);
}
.mcq-option.show-correct .opt-letter {
  background: var(--ok);
  color: #fff;
}
.mcq-option.show-wrong {
  border-color: var(--bad);
  background: rgba(239, 68, 68, .12);
}
.mcq-option.show-wrong .opt-letter {
  background: var(--bad);
  color: #fff;
}
.mcq-option .opt-mark {
  font-size: 20px;
  font-weight: 700;
  margin-left: auto;
}

/* MCQ Result Card */
.mcq-result-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  margin-bottom: 10px;
  border-left-width: 4px;
}
.mcq-result-card.ok { border-left-color: var(--ok); }
.mcq-result-card.bad { border-left-color: var(--bad); }
.mcq-result-card .mcq-rc-header {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}
.mcq-result-card .mcq-rc-q {
  font-weight: 600;
}
.mcq-result-card .mcq-rc-row {
  display: flex;
  gap: 12px;
  font-size: 13px;
  margin-top: 6px;
  flex-wrap: wrap;
}
.mcq-result-card .mcq-rc-row strong { color: var(--text-muted); }

/* =============== Fullscreen tweaks =============== */
:fullscreen .topbar { display: none; }
:fullscreen .footer { display: none; }
:fullscreen #app { margin-top: 12px; }
:fullscreen .app-modes { display: none; }