:root {
  color-scheme: light;
  --red-900: #6f1f25;
  --red-800: #86262c;
  --red-700: #9b2b31;
  --red-100: #f5e3e4;
  --red-050: #fff7f7;
  --ink: #24191b;
  --muted: #716366;
  --line: #e9dddd;
  --paper: #ffffff;
  --soft: #fbf8f8;
  --shadow: 0 18px 44px rgba(111, 31, 37, 0.1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  color: var(--ink);
  background: #fbfbfb;
}

button, input, a { font: inherit; }
button { cursor: pointer; }

.library-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 4.5rem;
  padding: 0.8rem clamp(1rem, 4vw, 3.5rem);
  border-bottom: 1px solid rgba(233, 221, 221, 0.8);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(20px);
}

.library-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 900;
}

.brand-mark {
  display: grid;
  width: 2.45rem;
  height: 2.45rem;
  place-items: center;
  border-radius: 0.55rem;
  color: white;
  background: var(--red-700);
}

.library-nav-links { display: flex; gap: 0.35rem; }

.library-nav-links a {
  padding: 0.6rem 0.8rem;
  border-radius: 0.45rem;
  color: var(--muted);
  text-decoration: none;
  font-weight: 800;
}

.library-nav-links a.active,
.library-nav-links a:hover {
  color: var(--red-900);
  background: var(--red-050);
}

.library-main {
  width: min(76rem, calc(100% - 2rem));
  margin: 0 auto;
  padding: clamp(3rem, 7vw, 6.5rem) 0 6rem;
}

.library-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 2rem;
  align-items: end;
  padding-bottom: clamp(3rem, 7vw, 6rem);
}

.eyebrow {
  margin: 0 0 0.6rem;
  color: var(--red-700);
  font-size: 0.82rem;
  font-weight: 900;
}

.library-hero h1 {
  margin: 0;
  color: var(--red-900);
  font-size: clamp(3.4rem, 9vw, 7.5rem);
  line-height: 0.95;
  letter-spacing: 0;
}

.library-hero p:not(.eyebrow) {
  max-width: 42rem;
  margin: 1.2rem 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.3rem);
  line-height: 1.7;
}

.library-count {
  min-width: 9rem;
  padding: 1.2rem;
  border-left: 3px solid var(--red-700);
}

.library-count strong,
.library-count span { display: block; }
.library-count strong { font-size: 2.6rem; }
.library-count span { color: var(--muted); }

.library-toolbar {
  display: grid;
  grid-template-columns: auto minmax(15rem, 1fr);
  gap: 1rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: white;
  box-shadow: var(--shadow);
}

.stage-switcher {
  display: flex;
  gap: 0.35rem;
  padding: 0.3rem;
  border-radius: 0.4rem;
  background: var(--red-050);
}

.stage-filter {
  min-height: 3rem;
  padding: 0.65rem 1rem;
  border: 0;
  border-radius: 0.35rem;
  color: var(--red-900);
  background: transparent;
  font-weight: 900;
}

.stage-filter.active { color: white; background: var(--red-800); }

.search-box {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-height: 3.6rem;
  padding: 0 1rem;
  border: 1px solid var(--line);
  border-radius: 0.45rem;
  background: var(--soft);
}

.search-box span { color: var(--red-700); font-size: 1.1rem; }

.search-box input {
  width: 100%;
  border: 0;
  outline: 0;
  color: var(--ink);
  background: transparent;
}

.library-results { margin-top: clamp(3rem, 6vw, 5rem); }

.result-section + .result-section { margin-top: 5rem; }

.result-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line);
}

.result-heading h2 { margin: 0; font-size: clamp(1.8rem, 4vw, 3rem); }
.result-heading p { max-width: 36rem; margin: 0; color: var(--muted); line-height: 1.6; }

.theme-grid,
.grammar-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.4rem;
  margin-top: 1.5rem;
}

.theme-card,
.grammar-card {
  min-height: 16rem;
  padding: clamp(1.25rem, 3vw, 2rem);
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: white;
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.entry-list { display:grid; gap:.55rem; margin-top:1.25rem; }
.word-entry { border:1px solid var(--line); border-radius:.4rem; background:var(--soft); }
.word-entry summary { display:flex; align-items:center; justify-content:space-between; gap:1rem; padding:.8rem; cursor:pointer; list-style:none; }
.word-entry summary::-webkit-details-marker { display:none; }
.word-entry summary span:first-child { display:grid; gap:.2rem; }
.word-entry summary strong { color:var(--red-900); }
.lexicon-ipa { display:block;margin:.25rem 0;color:var(--muted);font-family:"Segoe UI Symbol",Arial,sans-serif; }
.word-entry summary small,.example-list small,.entry-body small { display:block; color:var(--muted); line-height:1.5; }
.entry-meaning { color:var(--muted); text-align:right; }
.entry-body { display:grid; gap:.7rem; padding:0 .8rem .8rem; border-top:1px solid var(--line); }
.entry-body p { margin:.7rem 0 0; }
.entry-body strong { display:block; margin-bottom:.2rem; color:var(--red-800); font-size:.78rem; }
.entry-cia-link { display:inline-flex;margin-top:.5rem;color:var(--red-800);font-weight:900;text-decoration:none; }
.example-list { display:grid; gap:.55rem; margin-top:1rem; }
.example-list p { margin:0; padding:.75rem; border-left:3px solid var(--red-700); background:var(--red-050); }
.grammar-rule { color:var(--ink) !important; }
.mini-quiz { margin-top:1rem; padding:.9rem; border:1px solid var(--line); border-radius:.4rem; background:var(--soft); }
.mini-quiz summary { color:var(--red-800); cursor:pointer; font-weight:900; }
.mini-quiz ol { padding-left:1.35rem; line-height:1.7; }
.quiz-answer { padding-top:.8rem; border-top:1px solid var(--line); }
.quiz-answer strong { display:block; color:var(--red-800); }

.theme-card:hover,
.grammar-card:hover {
  transform: translateY(-3px);
  border-color: #d9bfc1;
  box-shadow: var(--shadow);
}

.card-label {
  color: var(--red-700);
  font-size: 0.8rem;
  font-weight: 900;
}

.theme-card h3,
.grammar-card h3 {
  margin: 0.55rem 0 0;
  font-size: clamp(1.35rem, 2.5vw, 2rem);
}

.theme-card p,
.grammar-card p {
  margin: 0.8rem 0 0;
  color: var(--muted);
  line-height: 1.7;
}

.word-list,
.unit-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0;
  margin: 1.25rem 0 0;
  list-style: none;
}

.word-list li,
.unit-list li {
  padding: 0.45rem 0.65rem;
  border: 1px solid var(--line);
  border-radius: 0.35rem;
  color: var(--ink);
  background: var(--soft);
}

.mistake-note {
  margin-top: 1.2rem;
  padding: 1rem;
  border-left: 3px solid var(--red-700);
  border-radius: 0.35rem;
  background: var(--red-050);
}

.mistake-note strong { color: var(--red-900); }
.card-link { display:inline-flex; margin-top:1rem; color:var(--red-800); font-weight:900; text-decoration:none; }
.card-link:hover { text-decoration:underline; }
.empty-state { padding: 4rem 1rem; color: var(--muted); text-align: center; }
.library-footer { margin-top: 5rem; padding-top: 1.5rem; border-top: 1px solid var(--line); color: var(--muted); }

/* Learning stages stay closed by default, so five thousand cards never become one long wall. */
.stage-section { border-bottom:1px solid var(--line); }
.stage-section + .stage-section { margin-top:0; }
.stage-section > summary { cursor:pointer;list-style:none;padding:1.6rem 0; }
.stage-section > summary::-webkit-details-marker,
.word-pack > summary::-webkit-details-marker { display:none; }
.stage-section > summary::after { content:"＋";flex:0 0 auto;color:var(--red-800);font-size:1.4rem;font-weight:400; }
.stage-section[open] > summary::after { content:"−"; }
.stage-section[open] > summary { border-bottom:0; }
.stage-meta { display:grid;grid-template-columns:auto auto;align-items:baseline;gap:.25rem;color:var(--muted);text-align:right; }
.stage-meta strong { color:var(--red-900);font-size:1.4rem; }
.stage-meta small { grid-column:1/-1;display:block;max-width:24rem;line-height:1.45; }
.stage-section > .theme-grid { margin:0;padding:0 0 2.5rem; }
.word-pack { min-height:0;padding:0;overflow:hidden; }
.word-pack[open] { grid-column:1/-1; }
.word-pack > summary { display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:1.25rem;cursor:pointer;list-style:none; }
.word-pack > summary strong { display:block;margin-top:.3rem;color:var(--ink);font-size:1.25rem; }
.pack-chevron::before { content:"＋";color:var(--red-800);font-size:1.2rem; }
.word-pack[open] .pack-chevron::before { content:"−"; }
.pack-actions { display:none;align-items:center;justify-content:space-between;gap:1rem;padding:0 1.25rem 1rem;color:var(--muted);font-size:.85rem; }
.word-pack[open] .pack-actions { display:flex; }
.word-pack .card-link { flex:0 0 auto;margin:0; }
.word-pack .entry-list { grid-template-columns:repeat(2,minmax(0,1fr));gap:0;margin:0;padding:0 1.25rem 1.25rem;border-top:1px solid var(--line); }
.word-pack .word-entry { border:0;border-bottom:1px solid var(--line);border-radius:0;background:transparent; }
.word-pack .word-entry:nth-child(odd) { border-right:1px solid var(--line); }
.word-pack .word-entry summary { min-height:4.5rem; }
.word-pack .entry-body { background:var(--soft); }

.library-actions { display:flex;align-items:center;gap:1rem;flex-wrap:wrap;margin-top:1.5rem; }
.primary-link,.text-link { font-weight:900;text-decoration:none; }
.primary-link { padding:.85rem 1rem;border-radius:.4rem;color:#fff;background:var(--red-800); }
.text-link { color:var(--red-800); }
.lexicon-note { display:grid;grid-template-columns:minmax(12rem,.45fr) minmax(0,1fr);gap:2rem;padding:2rem 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line); }
.lexicon-note strong { color:var(--red-900);font-size:1.35rem; }
.lexicon-note p { margin:0;color:var(--muted);line-height:1.75; }
.lexicon-toolbar { grid-template-columns:auto minmax(15rem,1fr) auto;margin-top:4rem; }
.select-box { display:flex;align-items:center;gap:.6rem;padding:0 1rem;border:1px solid var(--line);border-radius:.45rem;background:var(--soft);font-weight:800; }
.select-box select { min-height:3.5rem;border:0;outline:0;color:var(--ink);background:transparent; }
.lexicon-summary { display:flex;align-items:baseline;gap:.35rem;margin:2.5rem 0 1rem;color:var(--muted); }
.lexicon-summary strong { color:var(--red-900);font-size:1.8rem; }
.lexicon-summary #page-label { margin-left:auto; }
.lexicon-list { border-top:1px solid var(--line); }
.lexicon-row { display:grid;grid-template-columns:5.5rem minmax(12rem,.75fr) minmax(16rem,1.1fr) minmax(14rem,1fr);gap:1.25rem;align-items:center;padding:1.25rem 0;border-bottom:1px solid var(--line); }
.lexicon-rank { display:grid;color:var(--muted);font-size:.72rem; }
.lexicon-rank strong { color:var(--ink);font-size:1.1rem; }
.lexicon-word h2 { margin:.4rem 0 .2rem;color:var(--red-900);font-size:1.3rem;letter-spacing:0; }
.lexicon-word p,.lexicon-meaning small { display:block;margin:0;color:var(--muted);font-size:.82rem;line-height:1.45; }
.lexicon-meaning strong { display:block;line-height:1.55; }
.quality-badge,.cefr-badge { display:inline-flex;margin-right:.35rem;padding:.2rem .4rem;border:1px solid var(--line);border-radius:.25rem;color:var(--muted);font-size:.68rem;font-weight:900; }
.quality-badge.curated { border-color:var(--red-700);color:var(--red-800);background:var(--red-050); }
.lexicon-example { padding:.75rem;border-left:3px solid var(--red-700);background:var(--red-050); }
.lexicon-example summary { color:var(--red-800);cursor:pointer;font-weight:900; }
.lexicon-example p { margin:.65rem 0 0;line-height:1.55; }
.lexicon-example small { display:block;margin-top:.35rem;color:var(--muted);line-height:1.5; }
.lexicon-example small b { margin-right:.45rem;color:var(--red-800); }
.word-forms { display:flex;gap:.45rem;flex-wrap:wrap; }
.word-forms span { padding:.3rem .45rem;border:1px solid var(--line);border-radius:.3rem;background:#fff;font-size:.82rem; }
.word-forms b { color:var(--red-800); }
.lexicon-study-link { display:inline-block;margin-top:.8rem;color:var(--red-800);font-weight:900;text-decoration:none; }
.pagination { display:flex;align-items:center;justify-content:center;gap:1rem;margin-top:2.5rem; }
.pagination button { min-width:6rem;padding:.7rem 1rem;border:1px solid var(--line);border-radius:.35rem;color:var(--red-900);background:#fff;font-weight:900; }
.pagination button:disabled { cursor:not-allowed;opacity:.4; }

@media (max-width: 760px) {
  .library-nav { align-items: flex-start; flex-direction: column; }
  .library-nav-links { width: 100%; overflow-x: auto; }
  .library-nav-links a { flex:0 0 auto;white-space:nowrap; }
  .library-hero, .library-toolbar { grid-template-columns: 1fr; }
  .library-count { border-left: 0; border-top: 3px solid var(--red-700); }
  .stage-switcher { display: grid; grid-template-columns: repeat(3, 1fr); }
  .theme-grid, .grammar-grid { grid-template-columns: 1fr; }
  .result-heading { align-items: flex-start; flex-direction: column; }
  .lexicon-note,.lexicon-toolbar { grid-template-columns:1fr; }
  .select-box { justify-content:space-between; }
  .lexicon-row { grid-template-columns:4rem minmax(0,1fr);align-items:start; }
  .lexicon-meaning,.lexicon-example { grid-column:2; }
  .lexicon-summary { flex-wrap:wrap; }
  .lexicon-summary #page-label { width:100%;margin-left:0; }
  .stage-section > summary { align-items:flex-start; }
  .stage-meta { display:none; }
  .word-pack[open] { grid-column:auto; }
  .word-pack .entry-list { grid-template-columns:1fr; }
  .word-pack .word-entry:nth-child(odd) { border-right:0; }
  .pack-actions { align-items:flex-start;flex-direction:column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .theme-card, .grammar-card { transition: none; }
}