:root {
  --bg: #1a1a2e;
  --card-bg: #16213e;
  --card-2: #1e2a4a;
  --text: #e0e0e0;
  --text-secondary: #8a8a9a;
  --text-muted: #6a6a7a;
  --accent: #4fc3f7;
  --accent-2: #66bb6a;
  --warn: #ffb74d;
  --wrong: #ef5350;
  --border: #2a2a4a;
  --radius: 14px;
  --radius-sm: 8px;
  --shadow: 0 2px 14px rgba(0, 0, 0, 0.3);
  --header-h: 52px;
  --footer-h: 68px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;
  -webkit-tap-highlight-color: transparent;
  -webkit-font-smoothing: antialiased;
  overscroll-behavior: none;
}

/* ---------- Top bar ---------- */
.topbar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  height: var(--header-h);
  padding: 0 0.75rem;
  padding-top: env(safe-area-inset-top);
  height: calc(var(--header-h) + env(safe-area-inset-top));
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  z-index: 10;
}
.top-meta {
  flex: 1;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
}
#progress-label { font-variant-numeric: tabular-nums; }

.icon-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text);
  font-size: 1.25rem;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background .12s;
}
.icon-btn:hover { background: var(--card-2); }
.icon-btn:active { background: var(--border); }
.icon-btn[hidden] { display: none !important; }

/* ---------- Card scroll area ---------- */
.card-scroll {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 1rem;
  padding-left: max(1rem, env(safe-area-inset-left));
  padding-right: max(1rem, env(safe-area-inset-right));
  -webkit-overflow-scrolling: touch;
}

.card {
  max-width: 680px;
  margin: 0 auto;
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem 1.25rem 2rem;
  border: 1px solid var(--border);
}

.loading, .empty {
  padding: 3rem 1rem;
  text-align: center;
  color: var(--text-secondary);
}

/* ---------- Lemma header ---------- */
.lemma-row {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.lemma {
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--text);
  word-break: break-word;
}
.audio-btn {
  background: var(--accent);
  color: #0a1a2e;
  border: none;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  font-size: 1rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: transform .1s, background .15s;
}
.audio-btn:hover { background: #7dd3fc; }
.audio-btn:active { transform: scale(0.93); }
.audio-btn.speaking { background: var(--accent-2); }

.meta {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-top: 0.75rem;
  font-size: 0.8rem;
}
.meta span {
  padding: 0.2rem 0.55rem;
  background: var(--card-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text-secondary);
  font-weight: 500;
}
.meta .pos { color: var(--accent); border-color: var(--accent); }
.meta .priority-active_target { color: var(--accent-2); border-color: var(--accent-2); }
.meta .priority-recognition { color: var(--warn); }
.meta .tier-1 { background: rgba(138,138,154,0.1); }
.meta .tier-3 { background: rgba(79,195,247,0.12); color: var(--accent); }
.meta .tier-4 { background: rgba(102,187,106,0.12); color: var(--accent-2); }

.themes {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
  margin-top: 0.6rem;
}
.theme-tag {
  font-size: 0.72rem;
  padding: 0.15rem 0.5rem;
  background: var(--card-2);
  color: var(--text-secondary);
  border-radius: 4px;
  cursor: pointer;
}
.theme-tag:hover { color: var(--accent); }

/* ---------- Gloss ---------- */
.gloss {
  font-size: 1.15rem;
  font-weight: 500;
  margin-top: 1.25rem;
  padding: 1rem;
  background: var(--card-2);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent);
}
.test-mode .gloss,
.test-mode .examples .ex-en,
.test-mode .notes,
.test-mode .cue,
.test-mode .false-friend,
.test-mode .canadian-note,
.test-mode .list,
.test-mode .collocations {
  filter: blur(6px);
  transition: filter .25s;
  cursor: pointer;
}
.test-mode.reveal-all .gloss,
.test-mode.reveal-all .examples .ex-en,
.test-mode.reveal-all .notes,
.test-mode.reveal-all .cue,
.test-mode.reveal-all .false-friend,
.test-mode.reveal-all .canadian-note,
.test-mode.reveal-all .list,
.test-mode.reveal-all .collocations {
  filter: none;
}

.canadian-note, .false-friend {
  margin-top: 0.75rem;
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  line-height: 1.4;
}
.canadian-note {
  background: rgba(239,83,80,0.08);
  color: #f4a9a8;
  border-left: 3px solid #ef5350;
}
.false-friend {
  background: rgba(255,183,77,0.1);
  color: #ffd591;
  border-left: 3px solid var(--warn);
}

.verb-meta, .morph {
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.verb-meta span, .morph em {
  padding: 0.15rem 0.5rem;
  background: var(--card-2);
  border-radius: 4px;
  color: var(--text-secondary);
  font-style: normal;
}

/* ---------- Section headers ---------- */
.card h3 {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin: 1.35rem 0 0.6rem;
  font-weight: 700;
}

/* ---------- Examples ---------- */
.examples { margin-top: 0.25rem; }
.ex {
  margin-bottom: 0.85rem;
  padding: 0.75rem 0.85rem;
  background: var(--card-2);
  border-radius: var(--radius-sm);
}
.ex:last-child { margin-bottom: 0; }
.ex-fr-row {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
}
.ex-fr {
  flex: 1;
  font-size: 1.02rem;
  line-height: 1.45;
  color: var(--text);
}
.ex-audio {
  flex-shrink: 0;
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
  width: 30px;
  height: 30px;
  border-radius: 50%;
  font-size: 0.75rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background .12s;
}
.ex-audio:hover { background: var(--accent); color: #0a1a2e; }
.ex-audio.speaking { background: var(--accent-2); border-color: var(--accent-2); color: #0a1a2e; }
.ex-en {
  margin-top: 0.35rem;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.4;
}
.ex-note {
  margin-top: 0.35rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  font-style: italic;
  line-height: 1.4;
}

/* ---------- Collocations / lists ---------- */
.collocations, .list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.colloc, .list-item {
  padding: 0.3rem 0.65rem;
  background: var(--card-2);
  border-radius: 999px;
  font-size: 0.88rem;
  color: var(--text);
}

/* ---------- Notes / cue ---------- */
.notes, .cue {
  line-height: 1.55;
  font-size: 0.93rem;
  color: var(--text);
}
.notes { color: var(--text); }
.cue {
  margin-top: 0.25rem;
  padding: 0.85rem 0.95rem;
  background: rgba(79,195,247,0.08);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-sm);
  color: var(--text);
}

/* ---------- Cross-ref links ---------- */
.ref {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: rgba(79,195,247,0.4);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  cursor: pointer;
  transition: background .12s;
  padding: 0 2px;
  border-radius: 3px;
}
.ref:hover { background: rgba(79,195,247,0.15); text-decoration-color: var(--accent); }
.ref:active { background: rgba(79,195,247,0.3); }

/* ---------- Bottom bar ---------- */
.bottom-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding: 0.65rem 0.75rem;
  padding-bottom: max(0.65rem, env(safe-area-inset-bottom));
  background: var(--bg);
  border-top: 1px solid var(--border);
  z-index: 10;
}
.nav-btn {
  background: var(--card-bg);
  border: 1px solid var(--border);
  color: var(--text);
  width: 48px;
  height: 44px;
  font-size: 1.1rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background .12s;
}
.nav-btn:hover { background: var(--card-2); }
.nav-btn:active { background: var(--border); }

.mark-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 44px;
  border: 1px solid var(--border);
  background: var(--card-bg);
  color: var(--text);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  transition: background .12s, border-color .12s;
}
.mark-btn.difficult:hover { background: rgba(239,83,80,0.15); border-color: var(--wrong); color: #ff8a87; }
.mark-btn.known:hover { background: rgba(102,187,106,0.15); border-color: var(--accent-2); color: #8fcf92; }
.mark-btn:active { transform: scale(0.98); }
.mark-btn.active-known { border-color: var(--accent-2); background: rgba(102,187,106,0.1); color: #8fcf92; }
.mark-btn.active-difficult { border-color: var(--wrong); background: rgba(239,83,80,0.1); color: #ff8a87; }
.mark-icon { font-size: 1rem; }

/* ---------- Overlay ---------- */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(10,15,30,0.7);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 50;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}
.overlay[hidden] { display: none; }
@media (min-width: 540px) {
  .overlay { align-items: center; }
}
.overlay-panel {
  background: var(--card-bg);
  width: 100%;
  max-width: 620px;
  max-height: 85vh;
  overflow-y: auto;
  border-radius: var(--radius) var(--radius) 0 0;
  border: 1px solid var(--border);
  padding: 1.25rem 1rem 1.5rem;
  padding-bottom: max(1.5rem, env(safe-area-inset-bottom));
  animation: slideUp .22s ease-out;
}
@keyframes slideUp {
  from { transform: translateY(30px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}
@media (min-width: 540px) {
  .overlay-panel { border-radius: var(--radius); max-height: 80vh; }
}

.overlay-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}
.overlay-header h2 {
  font-size: 1.1rem;
  font-weight: 700;
}
.filter-section { margin-bottom: 1.25rem; }
.filter-section h3 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
  font-weight: 600;
}
.filter-section .hint {
  text-transform: none;
  letter-spacing: 0;
  font-weight: 400;
  color: var(--text-muted);
  font-size: 0.72rem;
}

.chip-row {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}
.chip-row.theme-chips {
  max-height: 30vh;
  overflow-y: auto;
  padding: 4px 0;
}
.chip {
  padding: 0.45rem 0.75rem;
  background: var(--card-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.85rem;
  color: var(--text);
  cursor: pointer;
  transition: background .12s, border-color .12s;
  user-select: none;
}
.chip:hover { border-color: var(--accent); }
.chip.active {
  background: rgba(79,195,247,0.12);
  border-color: var(--accent);
  color: var(--accent);
}
.chip .count {
  color: var(--text-muted);
  margin-left: 0.35rem;
  font-size: 0.78rem;
}
.chip.active .count { color: var(--accent); }

.check-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 0.75rem;
  background: var(--card-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.85rem;
  color: var(--text);
  cursor: pointer;
  user-select: none;
}
.check-chip input {
  margin: 0;
  accent-color: var(--accent);
}

.filter-footer {
  display: flex;
  gap: 0.5rem;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}
.ghost-btn {
  flex: 1;
  padding: 0.7rem;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  cursor: pointer;
  transition: background .12s;
}
.ghost-btn:hover { background: var(--card-2); }
.primary-btn {
  flex: 1;
  padding: 0.7rem;
  background: var(--accent);
  border: 1px solid var(--accent);
  color: #0a1a2e;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .12s;
}
.primary-btn:hover { background: #7dd3fc; }

/* ---------- Known state ---------- */
.card.known .lemma { color: var(--accent-2); }
.card.difficult .lemma { color: #ff8a87; }

/* Responsive: larger on bigger screens */
@media (min-width: 640px) {
  .lemma { font-size: 2.6rem; }
  .card { padding: 2rem 1.5rem 2.5rem; }
}