/* =====================================================================
   style.css — 小五長河成語教室
   hkp5exam.hk design tokens · Traditional Chinese · Mobile-first
   ===================================================================== */

/* ── 0. CSS Custom Properties ─────────────────────────────────────── */
:root {
  /* Brand palette */
  --c-navy:        #0B2545;
  --c-orange:      #F4A261;
  --c-cream:       #FDF6EC;
  --c-bg:          #FBFAF7;
  --c-text:        #1A1F2E;
  --c-text-muted:  #5C6478;
  --c-border:      #E4E1D9;

  /* Derived */
  --c-navy-light:  #1a3a6e;
  --c-orange-light: #fbd5b0;
  --c-orange-dark: #d97f3a;
  --c-green:       #2d7a4f;
  --c-green-light: #d4eddf;
  --c-red:         #c0392b;
  --c-red-light:   #fde8e6;
  --c-yellow:      #f39c12;
  --c-yellow-light:#fef9e7;

  /* Shape */
  --radius:        12px;
  --radius-lg:     20px;
  --radius-sm:     8px;
  --radius-pill:   100px;

  /* Shadow */
  --shadow-sm:     0 2px 8px rgba(11,37,69,0.07);
  --shadow-md:     0 4px 16px rgba(11,37,69,0.10);
  --shadow-lg:     0 8px 32px rgba(11,37,69,0.14);

  /* Typography */
  --font-body: 'PingFang TC', 'Hiragino Sans TC', 'Microsoft JhengHei', 'Microsoft YaHei', sans-serif;
  --font-size-base: 16px;

  /* Spacing scale */
  --s-1: 4px;
  --s-2: 8px;
  --s-3: 12px;
  --s-4: 16px;
  --s-5: 20px;
  --s-6: 24px;
  --s-8: 32px;
  --s-10: 40px;
  --s-12: 48px;
  --s-16: 64px;

  /* Transition */
  --transition: 200ms ease;
}

/* Dark mode overrides */
body.dark {
  --c-bg:         #0f1823;
  --c-cream:      #18243a;
  --c-text:       #e8eaf0;
  --c-text-muted: #8b95aa;
  --c-border:     #2a3650;
  --c-navy-light: #2a4a8a;
  --c-orange:     #f4a261;
  --shadow-sm:    0 2px 8px rgba(0,0,0,0.3);
  --shadow-md:    0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg:    0 8px 32px rgba(0,0,0,0.5);
}

/* ── 1. Reset & Base ──────────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 60px;
}

body {
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background var(--transition), color var(--transition);
}

h1, h2, h3, h4 {
  line-height: 1.3;
  font-weight: 700;
  color: var(--c-navy);
}

body.dark h1, body.dark h2, body.dark h3, body.dark h4 {
  color: #e8eaf0;
}

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

ul, ol { list-style: none; }

img { max-width: 100%; display: block; }

/* ── 2. Skip Link ─────────────────────────────────────────────────── */
.skip-link {
  position: fixed;
  top: var(--s-4);
  left: var(--s-4);
  background: var(--c-navy);
  color: #fff;
  padding: var(--s-2) var(--s-4);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  z-index: 9999;
  transform: translateY(-120%);
  transition: transform var(--transition);
}

.skip-link:focus {
  transform: translateY(0);
}

/* ── 3. Hero / Header ─────────────────────────────────────────────── */
.hero {
  background: var(--c-navy);
  color: #fff;
  padding-bottom: var(--s-16);
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--s-4) var(--s-6);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--s-3);
  font-size: 15px;
  font-weight: 600;
  color: rgba(255,255,255,0.95);
}

.logo {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--c-orange);
  color: var(--c-navy);
  font-size: 18px;
  font-weight: 800;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.ghost {
  background: rgba(255,255,255,0.12);
  border: 1.5px solid rgba(255,255,255,0.3);
  color: #fff;
  padding: var(--s-2) var(--s-4);
  border-radius: var(--radius-pill);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
}

.ghost:hover, .ghost:focus-visible {
  background: rgba(255,255,255,0.22);
  border-color: rgba(255,255,255,0.5);
  outline: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--s-8);
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--s-12) var(--s-6) 0;
}

@media (min-width: 760px) {
  .hero-grid {
    grid-template-columns: 1fr 340px;
    align-items: start;
  }
}

.eyebrow {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--c-orange);
  margin-bottom: var(--s-3);
}

.hero .eyebrow { color: var(--c-orange); }

.hero h1 {
  font-size: clamp(26px, 4vw, 40px);
  font-weight: 800;
  color: #fff;
  margin-bottom: var(--s-4);
  line-height: 1.25;
}

.lede {
  font-size: 15px;
  color: rgba(255,255,255,0.75);
  margin-bottom: var(--s-8);
  line-height: 1.75;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-3);
}

/* Primary / Secondary buttons */
.primary, a.primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--c-orange);
  color: var(--c-navy);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  padding: 10px var(--s-6);
  border-radius: var(--radius-pill);
  border: 2px solid transparent;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.primary:hover, a.primary:hover, .primary:focus-visible, a.primary:focus-visible {
  background: #e8913f;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(244,162,97,0.4);
  outline: none;
}

.secondary, a.secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  color: #fff;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 600;
  padding: 10px var(--s-6);
  border-radius: var(--radius-pill);
  border: 2px solid rgba(255,255,255,0.4);
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.secondary:hover, a.secondary:hover, .secondary:focus-visible, a.secondary:focus-visible {
  border-color: rgba(255,255,255,0.8);
  background: rgba(255,255,255,0.08);
  outline: none;
}

/* Secondary on light bg */
.section .secondary, .section .quiz-actions .secondary {
  color: var(--c-navy);
  border-color: var(--c-border);
}

body.dark .section .secondary, body.dark .section .quiz-actions .secondary {
  color: var(--c-text);
  border-color: var(--c-border);
}

.section .secondary:hover {
  border-color: var(--c-navy);
  background: rgba(11,37,69,0.06);
}

body.dark .section .secondary:hover {
  border-color: var(--c-text-muted);
  background: rgba(255,255,255,0.06);
}

/* Hero card */
.hero-card {
  background: rgba(255,255,255,0.08);
  border: 1.5px solid rgba(255,255,255,0.15);
  border-radius: var(--radius-lg);
  padding: var(--s-6);
  color: rgba(255,255,255,0.9);
}

.hero-card p {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--c-orange);
  margin-bottom: var(--s-3);
}

.hero-card h3 {
  color: #fff;
  font-size: 16px;
  margin-bottom: var(--s-4);
}

.hero-card ol {
  list-style: decimal;
  padding-left: 18px;
}

.hero-card ol li {
  font-size: 14px;
  margin-bottom: var(--s-2);
  color: rgba(255,255,255,0.82);
  line-height: 1.6;
}

/* Section source-card (exam tips) */
.source-card {
  background: var(--c-cream);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-6);
}

body.dark .source-card {
  background: #162035;
  border-color: var(--c-border);
}

.source-card h3 {
  font-size: 16px;
  margin-bottom: var(--s-3);
}

.source-card p, .source-card li {
  font-size: 14px;
  color: var(--c-text-muted);
  line-height: 1.7;
}

.source-card ul {
  list-style: disc;
  padding-left: 18px;
  margin: var(--s-3) 0;
}

.source-card ul li { margin-bottom: var(--s-2); }

.source-card strong { color: var(--c-text); font-weight: 700; }

body.dark .source-card strong { color: var(--c-text); }

/* ── 4. Sticky Tabs ───────────────────────────────────────────────── */
.tabs {
  display: flex;
  overflow-x: auto;
  gap: 0;
  background: var(--c-cream);
  border-bottom: 2px solid var(--c-border);
  position: sticky;
  top: 0;
  z-index: 100;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.tabs::-webkit-scrollbar { display: none; }

body.dark .tabs {
  background: #0f1823;
  border-bottom-color: var(--c-border);
}

.tabs a {
  padding: var(--s-4) var(--s-5);
  font-size: 13px;
  font-weight: 600;
  color: var(--c-text-muted);
  white-space: nowrap;
  border-bottom: 3px solid transparent;
  transition: color var(--transition), border-color var(--transition);
  flex-shrink: 0;
}

.tabs a:hover {
  color: var(--c-navy);
  border-bottom-color: var(--c-orange);
}

body.dark .tabs a:hover { color: var(--c-text); }

.tabs a.active {
  color: var(--c-navy);
  border-bottom-color: var(--c-orange);
}

body.dark .tabs a.active { color: var(--c-text); }

/* ── 5. Sections ─────────────────────────────────────────────────── */
.section {
  padding: var(--s-16) var(--s-6);
  max-width: 1100px;
  margin: 0 auto;
}

/* Override max-width for full-width alt sections */
section#fill, section#trap, section#mock {
  max-width: 100%;
  padding-left: 0;
  padding-right: 0;
}

section#fill > *, section#trap > *, section#mock > * {
  max-width: 1100px;
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--s-6);
  padding-right: var(--s-6);
}

section#fill, section#trap, section#mock {
  padding-top: var(--s-16);
  padding-bottom: var(--s-16);
  background: var(--c-cream);
}

body.dark section#fill, body.dark section#trap, body.dark section#mock {
  background: #12192a;
}

.section-head {
  max-width: 680px;
  margin-bottom: var(--s-10);
}

.section-head h2 {
  font-size: clamp(22px, 3vw, 30px);
  margin-bottom: var(--s-3);
}

.section-head p {
  font-size: 15px;
  color: var(--c-text-muted);
  line-height: 1.75;
}

/* ── 6. Filter Bar ────────────────────────────────────────────────── */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-2);
  margin-bottom: var(--s-8);
}

.filter-btn, .level-btn {
  padding: 6px var(--s-4);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-pill);
  background: var(--c-bg);
  color: var(--c-text-muted);
  cursor: pointer;
  transition: all var(--transition);
}

body.dark .filter-btn, body.dark .level-btn {
  background: #162035;
  border-color: var(--c-border);
  color: var(--c-text-muted);
}

.filter-btn:hover, .level-btn:hover {
  border-color: var(--c-navy);
  color: var(--c-navy);
  background: rgba(11,37,69,0.05);
}

body.dark .filter-btn:hover, body.dark .level-btn:hover {
  border-color: var(--c-text-muted);
  color: var(--c-text);
  background: rgba(255,255,255,0.06);
}

.filter-btn.active, .level-btn.active {
  background: var(--c-navy);
  border-color: var(--c-navy);
  color: #fff;
}

body.dark .filter-btn.active, body.dark .level-btn.active {
  background: var(--c-navy-light);
  border-color: var(--c-navy-light);
  color: #fff;
}

/* ── 7. Idiom Grid & Cards ────────────────────────────────────────── */
.idiom-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--s-4);
}

@media (min-width: 520px) {
  .idiom-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 900px) {
  .idiom-grid { grid-template-columns: repeat(3, 1fr); }
}

.idiom-card {
  background: var(--c-cream);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-5) var(--s-5) var(--s-4);
  cursor: pointer;
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
  position: relative;
  overflow: hidden;
}

body.dark .idiom-card {
  background: #162035;
  border-color: var(--c-border);
}

.idiom-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--c-orange);
}

.idiom-card:focus-visible {
  outline: 3px solid var(--c-orange);
  outline-offset: 2px;
}

.idiom-card.expanded {
  border-color: var(--c-orange);
  box-shadow: var(--shadow-lg);
}

.card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--s-2);
  margin-bottom: var(--s-3);
}

.idiom-chars {
  font-size: clamp(22px, 4vw, 28px);
  font-weight: 800;
  color: var(--c-navy);
  letter-spacing: 0.04em;
  line-height: 1.2;
}

body.dark .idiom-chars { color: #e8eaf0; }

.card-badges {
  display: flex;
  flex-direction: column;
  gap: var(--s-1);
  align-items: flex-end;
  flex-shrink: 0;
}

.badge {
  font-size: 11px;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  white-space: nowrap;
}

.badge-lesson {
  background: rgba(11,37,69,0.1);
  color: var(--c-navy);
}

body.dark .badge-lesson {
  background: rgba(255,255,255,0.12);
  color: rgba(255,255,255,0.8);
}

.badge-tone-褒 {
  background: var(--c-green-light);
  color: var(--c-green);
}

.badge-tone-貶 {
  background: var(--c-red-light);
  color: var(--c-red);
}

.badge-tone-中 {
  background: var(--c-yellow-light);
  color: var(--c-yellow);
}

.card-romanization {
  font-size: 12px;
  color: var(--c-text-muted);
  margin-bottom: var(--s-3);
  line-height: 1.5;
}

.card-romanization span {
  display: block;
}

.card-category {
  font-size: 11px;
  font-weight: 600;
  color: var(--c-orange);
  margin-bottom: var(--s-2);
}

.card-meaning {
  font-size: 14px;
  color: var(--c-text);
  line-height: 1.65;
}

body.dark .card-meaning { color: var(--c-text); }

.card-expand {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.3s ease;
}

.idiom-card.expanded .card-expand {
  max-height: 600px;
}

.card-divider {
  height: 1px;
  background: var(--c-border);
  margin: var(--s-4) 0;
}

.card-expand-inner {
  padding-top: var(--s-1);
}

.card-expand-inner p {
  font-size: 13px;
  color: var(--c-text-muted);
  margin-bottom: var(--s-3);
  line-height: 1.7;
}

.card-expand-inner strong { color: var(--c-text); font-weight: 700; }

.card-expand-inner .example-sentence {
  background: rgba(244,162,97,0.1);
  border-left: 3px solid var(--c-orange);
  padding: var(--s-3) var(--s-4);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 14px;
  color: var(--c-text);
  margin-bottom: var(--s-3);
  line-height: 1.7;
}

body.dark .card-expand-inner .example-sentence {
  background: rgba(244,162,97,0.07);
}

.trap-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--s-2);
  background: var(--c-red-light);
  color: var(--c-red);
  font-size: 12px;
  font-weight: 600;
  padding: var(--s-2) var(--s-3);
  border-radius: var(--radius-sm);
  margin-bottom: var(--s-3);
}

body.dark .trap-badge {
  background: rgba(192,57,43,0.2);
  color: #e87c73;
}

.near-opp-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-3);
  font-size: 13px;
}

.near-opp-row span { color: var(--c-text-muted); }

.near-opp-row strong { color: var(--c-navy); }

body.dark .near-opp-row strong { color: var(--c-text); }

.card-expand-toggle {
  font-size: 12px;
  color: var(--c-text-muted);
  margin-top: var(--s-4);
  text-align: right;
}

/* ── 8. Audio Section ─────────────────────────────────────────────── */
.audio-section { background: var(--c-bg); }

.audio-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s-3);
  margin-bottom: var(--s-8);
}

.audio-status {
  font-size: 13px;
  color: var(--c-text-muted);
  font-weight: 500;
}

.audio-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--s-4);
}

@media (min-width: 640px) {
  .audio-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 900px) {
  .audio-grid { grid-template-columns: repeat(3, 1fr); }
}

.audio-card {
  background: var(--c-cream);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-5);
  display: flex;
  flex-direction: column;
  gap: var(--s-3);
  transition: box-shadow var(--transition);
}

body.dark .audio-card {
  background: #162035;
  border-color: var(--c-border);
}

.audio-card:hover { box-shadow: var(--shadow-sm); }

.audio-card h3 {
  font-size: 15px;
  margin-bottom: 0;
}

.audio-card p {
  font-size: 13px;
  color: var(--c-text-muted);
  line-height: 1.6;
  flex: 1;
}

.listen-btn {
  align-self: flex-start;
  background: transparent;
  border: 1.5px solid var(--c-navy);
  color: var(--c-navy);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  padding: 6px var(--s-4);
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: all var(--transition);
}

body.dark .listen-btn {
  border-color: var(--c-text-muted);
  color: var(--c-text);
}

.listen-btn:hover {
  background: var(--c-navy);
  color: #fff;
}

body.dark .listen-btn:hover {
  background: var(--c-navy-light);
  color: #fff;
}

.listen-btn.playing {
  background: var(--c-orange);
  border-color: var(--c-orange);
  color: var(--c-navy);
}

.audio-note {
  margin-top: var(--s-6);
  font-size: 13px;
  color: var(--c-text-muted);
  font-style: italic;
}

/* ── 9. Fill Drill ────────────────────────────────────────────────── */
.fill-list {
  display: flex;
  flex-direction: column;
  gap: var(--s-4);
}

.fill-item {
  background: #fff;
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-5);
  transition: border-color var(--transition);
}

body.dark .fill-item {
  background: #162035;
  border-color: var(--c-border);
}

.fill-item.correct { border-color: var(--c-green); }
.fill-item.wrong   { border-color: var(--c-red); }

.fill-q-num {
  font-size: 11px;
  font-weight: 700;
  color: var(--c-text-muted);
  margin-bottom: var(--s-2);
}

.fill-sentence {
  font-size: 15px;
  color: var(--c-text);
  margin-bottom: var(--s-4);
  line-height: 1.75;
}

.fill-input-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s-2);
}

.fill-input {
  font-family: var(--font-body);
  font-size: 16px;
  width: 120px;
  padding: 8px 12px;
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-sm);
  background: var(--c-bg);
  color: var(--c-text);
  transition: border-color var(--transition);
}

.fill-input:focus {
  outline: none;
  border-color: var(--c-navy);
}

body.dark .fill-input {
  background: #0f1823;
  border-color: var(--c-border);
  color: var(--c-text);
}

.fill-hint-btn, .fill-check-btn {
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  padding: 7px 14px;
  border-radius: var(--radius-pill);
  border: 1.5px solid var(--c-border);
  cursor: pointer;
  transition: all var(--transition);
}

.fill-hint-btn {
  background: var(--c-yellow-light);
  color: #8a6500;
  border-color: var(--c-yellow-light);
}

body.dark .fill-hint-btn {
  background: rgba(243,156,18,0.15);
  color: var(--c-yellow);
  border-color: transparent;
}

.fill-hint-btn:hover { opacity: 0.8; }

.fill-check-btn {
  background: var(--c-navy);
  color: #fff;
  border-color: var(--c-navy);
}

.fill-check-btn:hover { background: var(--c-navy-light); }

body.dark .fill-check-btn {
  background: var(--c-navy-light);
  border-color: var(--c-navy-light);
}

.fill-feedback {
  margin-top: var(--s-3);
  font-size: 13px;
  font-weight: 600;
  padding: var(--s-2) var(--s-3);
  border-radius: var(--radius-sm);
  display: none;
}

.fill-feedback.show { display: block; }

.fill-feedback.success {
  background: var(--c-green-light);
  color: var(--c-green);
}

.fill-feedback.error {
  background: var(--c-red-light);
  color: var(--c-red);
}

body.dark .fill-feedback.success {
  background: rgba(45,122,79,0.2);
  color: #5fcb8a;
}

body.dark .fill-feedback.error {
  background: rgba(192,57,43,0.2);
  color: #e87c73;
}

.fill-summary {
  margin-top: var(--s-8);
  font-size: 15px;
  font-weight: 600;
  color: var(--c-navy);
  text-align: center;
}

body.dark .fill-summary { color: var(--c-text); }

/* ── 10. Meaning List ─────────────────────────────────────────────── */
.meaning-list {
  display: flex;
  flex-direction: column;
  gap: var(--s-6);
}

.meaning-item {
  background: var(--c-cream);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-5);
}

body.dark .meaning-item {
  background: #162035;
  border-color: var(--c-border);
}

.meaning-q-num {
  font-size: 11px;
  font-weight: 700;
  color: var(--c-text-muted);
  margin-bottom: var(--s-2);
}

.meaning-sentence {
  font-size: 15px;
  line-height: 1.75;
  margin-bottom: var(--s-4);
}

.meaning-sentence u {
  text-decoration-color: var(--c-orange);
  text-underline-offset: 3px;
  text-decoration-thickness: 2px;
}

.meaning-options {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--s-2);
}

@media (min-width: 640px) {
  .meaning-options { grid-template-columns: repeat(4, 1fr); }
}

.meaning-opt-btn {
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  padding: var(--s-3) var(--s-3);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-sm);
  background: var(--c-bg);
  color: var(--c-text);
  cursor: pointer;
  transition: all var(--transition);
  letter-spacing: 0.03em;
}

body.dark .meaning-opt-btn {
  background: #0f1823;
  border-color: var(--c-border);
  color: var(--c-text);
}

.meaning-opt-btn:hover:not(:disabled) {
  border-color: var(--c-navy);
  background: rgba(11,37,69,0.05);
}

.meaning-opt-btn.correct-choice {
  background: var(--c-green-light);
  border-color: var(--c-green);
  color: var(--c-green);
}

.meaning-opt-btn.wrong-choice {
  background: var(--c-red-light);
  border-color: var(--c-red);
  color: var(--c-red);
}

body.dark .meaning-opt-btn.correct-choice {
  background: rgba(45,122,79,0.2);
  border-color: #5fcb8a;
  color: #5fcb8a;
}

body.dark .meaning-opt-btn.wrong-choice {
  background: rgba(192,57,43,0.2);
  border-color: #e87c73;
  color: #e87c73;
}

.meaning-opt-btn:disabled { cursor: default; opacity: 0.8; }

.meaning-feedback {
  margin-top: var(--s-4);
  font-size: 13px;
  padding: var(--s-3) var(--s-4);
  border-radius: var(--radius-sm);
  display: none;
  line-height: 1.6;
}

.meaning-feedback.show { display: block; }

.meaning-feedback.success {
  background: var(--c-green-light);
  color: var(--c-green);
}

.meaning-feedback.error {
  background: var(--c-red-light);
  color: var(--c-red);
}

body.dark .meaning-feedback.success {
  background: rgba(45,122,79,0.2);
  color: #5fcb8a;
}

body.dark .meaning-feedback.error {
  background: rgba(192,57,43,0.2);
  color: #e87c73;
}

/* ── 11. Trap Zone ────────────────────────────────────────────────── */
.trap-list {
  display: flex;
  flex-direction: column;
  gap: var(--s-5);
}

.trap-item {
  background: #fff;
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-5);
  transition: border-color var(--transition);
}

body.dark .trap-item {
  background: #162035;
  border-color: var(--c-border);
}

.trap-item.trap-solved { border-color: var(--c-green); }
.trap-item.trap-failed { border-color: var(--c-red); }

.trap-q-num {
  font-size: 11px;
  font-weight: 700;
  color: var(--c-text-muted);
  margin-bottom: var(--s-2);
}

.trap-sentence {
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-text);
  margin-bottom: var(--s-4);
}

.trap-idiom-chars {
  display: inline-flex;
  gap: 2px;
}

.trap-char-btn {
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 700;
  width: 34px;
  height: 34px;
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-sm);
  background: var(--c-cream);
  color: var(--c-navy);
  cursor: pointer;
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

body.dark .trap-char-btn {
  background: #0f1823;
  border-color: var(--c-border);
  color: var(--c-text);
}

.trap-char-btn:hover:not(:disabled) {
  background: var(--c-navy);
  color: #fff;
  border-color: var(--c-navy);
}

.trap-char-btn.wrong-trap {
  background: var(--c-red-light);
  border-color: var(--c-red);
  color: var(--c-red);
  animation: shake 0.3s ease;
}

.trap-char-btn.correct-trap {
  background: var(--c-red-light);
  border-color: var(--c-red);
  color: var(--c-red);
  font-weight: 900;
}

.trap-char-btn:disabled { cursor: default; }

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25%       { transform: translateX(-4px); }
  75%       { transform: translateX(4px); }
}

.trap-feedback {
  margin-top: var(--s-3);
  font-size: 13px;
  padding: var(--s-3) var(--s-4);
  border-radius: var(--radius-sm);
  display: none;
  line-height: 1.6;
}

.trap-feedback.show { display: block; }

.trap-feedback.success {
  background: var(--c-green-light);
  color: var(--c-green);
}

.trap-feedback.hint {
  background: var(--c-yellow-light);
  color: #8a6500;
}

body.dark .trap-feedback.success {
  background: rgba(45,122,79,0.2);
  color: #5fcb8a;
}

body.dark .trap-feedback.hint {
  background: rgba(243,156,18,0.15);
  color: var(--c-yellow);
}

/* ── 12. Exam Grid ────────────────────────────────────────────────── */
.exam-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--s-5);
}

@media (min-width: 640px) {
  .exam-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 900px) {
  .exam-grid { grid-template-columns: repeat(3, 1fr); }
}

/* Force first item (hero-card) to span full width on light bg */
section#exam .hero-card {
  background: var(--c-navy);
  color: rgba(255,255,255,0.9);
  grid-column: 1 / -1;
}

@media (min-width: 640px) {
  section#exam .hero-card {
    grid-column: span 1;
  }
}

.checklist { list-style: none; padding: 0; }

.checklist li {
  display: flex;
  align-items: flex-start;
  gap: var(--s-3);
  margin-bottom: var(--s-3);
  font-size: 14px;
  color: rgba(255,255,255,0.85);
  line-height: 1.6;
}

.check-btn {
  flex-shrink: 0;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  border: 1.5px solid rgba(255,255,255,0.4);
  background: rgba(255,255,255,0.12);
  color: #fff;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}

.check-btn:hover {
  background: rgba(255,255,255,0.25);
  border-color: rgba(255,255,255,0.7);
}

.check-btn.checked {
  background: var(--c-orange);
  border-color: var(--c-orange);
  color: var(--c-navy);
}

/* ── 13. Mock Paper ───────────────────────────────────────────────── */
.quiz-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s-3);
  margin-bottom: var(--s-8);
}

.mock-list {
  display: flex;
  flex-direction: column;
  gap: var(--s-5);
}

/* Mock fill item */
.mock-item {
  background: #fff;
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-5);
}

body.dark .mock-item {
  background: #162035;
  border-color: var(--c-border);
}

.mock-item.mock-correct { border-color: var(--c-green); }
.mock-item.mock-wrong   { border-color: var(--c-red); }

.mock-item-type {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--c-text-muted);
  margin-bottom: var(--s-2);
}

.mock-item-q {
  font-size: 15px;
  line-height: 1.75;
  margin-bottom: var(--s-4);
  color: var(--c-text);
}

.mock-item-q u {
  text-decoration-color: var(--c-orange);
  text-underline-offset: 3px;
  text-decoration-thickness: 2px;
}

/* Mock options (for meaning-type in mock) */
.mock-opts {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--s-2);
}

.mock-opt-btn {
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  padding: var(--s-3);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-sm);
  background: var(--c-bg);
  color: var(--c-text);
  cursor: pointer;
  transition: all var(--transition);
  letter-spacing: 0.03em;
}

body.dark .mock-opt-btn {
  background: #0f1823;
  border-color: var(--c-border);
  color: var(--c-text);
}

.mock-opt-btn:hover:not(:disabled) {
  border-color: var(--c-navy);
  background: rgba(11,37,69,0.05);
}

.mock-opt-btn.selected {
  border-color: var(--c-navy);
  background: rgba(11,37,69,0.08);
}

body.dark .mock-opt-btn.selected {
  border-color: var(--c-text-muted);
  background: rgba(255,255,255,0.08);
}

/* Mock trap buttons */
.mock-trap-chars {
  display: inline-flex;
  gap: 2px;
}

.mock-trap-btn {
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 700;
  width: 34px;
  height: 34px;
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-sm);
  background: var(--c-cream);
  color: var(--c-navy);
  cursor: pointer;
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

body.dark .mock-trap-btn {
  background: #0f1823;
  border-color: var(--c-border);
  color: var(--c-text);
}

.mock-trap-btn:hover:not(:disabled) {
  background: var(--c-navy);
  color: #fff;
  border-color: var(--c-navy);
}

.mock-trap-btn.selected-trap {
  background: var(--c-yellow-light);
  border-color: var(--c-yellow);
  color: #8a6500;
}

/* Result card */
.result-card {
  margin-top: var(--s-8);
  background: var(--c-cream);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: var(--s-8);
  display: none;
}

body.dark .result-card {
  background: #162035;
  border-color: var(--c-border);
}

.result-card.show { display: block; }

.result-score {
  font-size: 48px;
  font-weight: 900;
  color: var(--c-navy);
  line-height: 1;
  margin-bottom: var(--s-2);
}

body.dark .result-score { color: var(--c-text); }

.result-time {
  font-size: 14px;
  color: var(--c-text-muted);
  margin-bottom: var(--s-6);
}

.result-breakdown {
  border-top: 1px solid var(--c-border);
  padding-top: var(--s-5);
}

.result-breakdown h3 {
  font-size: 15px;
  margin-bottom: var(--s-4);
}

.result-breakdown ul { padding: 0; }

.result-breakdown li {
  font-size: 14px;
  padding: var(--s-3) 0;
  border-bottom: 1px solid var(--c-border);
  line-height: 1.6;
  color: var(--c-text-muted);
}

.result-breakdown li:last-child { border-bottom: none; }

.result-breakdown .correct-ans {
  color: var(--c-green);
  font-weight: 700;
}

.result-breakdown .wrong-ans {
  color: var(--c-red);
  font-weight: 700;
}

/* ── 14. Footer ───────────────────────────────────────────────────── */
.footer {
  background: var(--c-navy);
  color: rgba(255,255,255,0.6);
  text-align: center;
  padding: var(--s-8) var(--s-6);
  font-size: 13px;
  line-height: 1.7;
}

body.dark .footer {
  background: #080f1a;
}

/* ── 15. Audio unsupported notice ─────────────────────────────────── */
.audio-unsupported {
  padding: var(--s-4);
  background: var(--c-yellow-light);
  border: 1.5px solid var(--c-yellow);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: #8a6500;
  margin-bottom: var(--s-6);
}

body.dark .audio-unsupported {
  background: rgba(243,156,18,0.15);
  border-color: rgba(243,156,18,0.4);
  color: var(--c-yellow);
}

/* ── 16. Misc / Utility ───────────────────────────────────────────── */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}

/* Active tab highlight on scroll */
.tabs a[aria-current="page"] {
  color: var(--c-navy);
  border-bottom-color: var(--c-orange);
}

/* Mobile tweaks */
@media (max-width: 400px) {
  .topbar { padding: var(--s-3) var(--s-4); }
  .brand span:last-child { display: none; }
  .meaning-options { grid-template-columns: 1fr; }
  .mock-opts { grid-template-columns: 1fr; }
}

/* ── 成語卡片內嵌朗讀／暫停按鈕 ─────────────────────── */
.card-audio-row {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}
.card-listen-btn,
.card-pause-btn {
  font-family: inherit;
  font-size: 0.92rem;
  font-weight: 600;
  padding: 0.45rem 0.9rem;
  border-radius: var(--radius, 10px);
  border: 1px solid var(--c-border, #d8dee9);
  cursor: pointer;
  transition: background 0.15s, transform 0.1s, box-shadow 0.15s;
  white-space: nowrap;
}
.card-listen-btn {
  background: var(--c-navy, #0B2545);
  color: #fff;
  border-color: var(--c-navy, #0B2545);
}
.card-listen-btn:hover {
  background: #14346a;
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(11, 37, 69, 0.25);
}
.card-pause-btn {
  background: #fff;
  color: var(--c-navy, #0B2545);
}
.card-pause-btn:hover {
  background: var(--c-cream, #FAF7F2);
  transform: translateY(-1px);
}
.card-listen-btn:focus-visible,
.card-pause-btn:focus-visible {
  outline: 2px solid var(--c-orange, #F4A261);
  outline-offset: 2px;
}