:root{
  --bg:#f4efe6;
  --paper:#fffaf1;
  --ink:#1e1d1a;
  --muted:#665f55;
  --line:#d8ccb8;
  --accent:#a04f2f;
  --accent-soft:#efd3bf;
  --deep:#253142;
  --deep-soft:#dde7f1;
  --shadow:0 18px 48px rgba(36,25,12,.08);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  color:var(--ink);
  background:
    radial-gradient(circle at top left, rgba(160,79,47,.12), transparent 32%),
    radial-gradient(circle at top right, rgba(37,49,66,.12), transparent 26%),
    linear-gradient(180deg, #f8f2e9 0%, var(--bg) 100%);
  font-family:"PingFang SC","Hiragino Sans GB","Noto Sans CJK SC","Microsoft YaHei",sans-serif;
  line-height:1.7;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.page-shell{max-width:1240px;margin:0 auto;padding:28px 24px 60px}
.topbar{
  display:flex;justify-content:space-between;align-items:center;gap:18px;
  padding:14px 18px;border:1px solid var(--line);border-radius:16px;
  background:rgba(255,250,241,.82);backdrop-filter:blur(10px);box-shadow:var(--shadow);
}
.brand{display:flex;flex-direction:column;gap:2px}
.brand-kicker{font-size:12px;letter-spacing:.12em;text-transform:uppercase;color:var(--accent)}
.brand-title{font-family:"Songti SC","STSong","Source Han Serif SC",serif;font-size:22px}
.nav-links{display:flex;gap:10px;flex-wrap:wrap}
.nav-links a,.chip,.toggle-answer{
  border:1px solid var(--line);border-radius:999px;padding:8px 14px;background:#fffdf8;
  font-size:13px;color:var(--muted)
}
.hero{
  display:grid;grid-template-columns:1.35fr .9fr;gap:24px;margin-top:24px;
}
.hero-main,.hero-side,.section-panel,.card,.chapter-card,.concept-card,.plate-card,.glossary-card,.source-item-deep,.viewer,.path-panel,.plate-route-group{
  background:var(--paper);border:1px solid var(--line);border-radius:24px;box-shadow:var(--shadow);
}
.hero-main{padding:34px;position:relative;overflow:hidden}
.hero-main:before{
  content:"";position:absolute;inset:auto -10% -22% auto;width:260px;height:260px;border-radius:50%;
  background:radial-gradient(circle, rgba(160,79,47,.22), transparent 68%);
}
.hero-main h1,.page-title{
  margin:10px 0 12px;font-size:52px;line-height:1.08;letter-spacing:0;
  font-family:"Songti SC","STSong","Source Han Serif SC",serif;
}
.hero-main p{color:var(--muted);max-width:780px}
.hero-meta{display:flex;gap:10px;flex-wrap:wrap;margin:18px 0 22px}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap}
.primary-btn,.secondary-btn{
  display:inline-flex;align-items:center;justify-content:center;padding:12px 18px;border-radius:999px;
  font-weight:600;border:1px solid transparent
}
.primary-btn{background:var(--ink);color:#fff}
.secondary-btn{background:#fff;border-color:var(--line);color:var(--ink)}
.hero-side{padding:22px;display:grid;gap:14px;align-content:start}
.stat{padding:14px 16px;border-radius:18px;background:#fff;border:1px solid var(--line)}
.stat-label{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}
.stat-value{font-size:28px;font-weight:700;margin-top:6px}
.section-block{margin-top:28px}
.section-heading{display:flex;justify-content:space-between;align-items:end;gap:16px;margin-bottom:14px}
.section-heading h2{margin:0;font-size:28px;font-family:"Songti SC","STSong","Source Han Serif SC",serif}
.section-heading p{margin:0;color:var(--muted);max-width:720px}
.grid-3,.grid-4,.grid-2{display:grid;gap:18px}
.grid-4{grid-template-columns:repeat(4,minmax(0,1fr))}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.chapter-card,.concept-card,.plate-card,.glossary-card,.card,.source-item-deep{padding:18px}
.chapter-card h3,.concept-card h3,.plate-card h3,.glossary-card h3,.card h3{margin:0 0 8px;font-size:20px;font-family:"Songti SC","STSong","Source Han Serif SC",serif}
.chapter-card p,.concept-card p,.plate-card p,.glossary-card p,.card p,.source-item-deep p{margin:0;color:var(--muted)}
.card-tags{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}
.cover-frame,.thumb-frame{
  background:#f8f4ed;border:1px solid var(--line);border-radius:18px;padding:12px;aspect-ratio:1.28/1;
  display:flex;align-items:center;justify-content:center;overflow:hidden;margin-bottom:14px;
}
.thumb-frame img{width:100%;height:100%;object-fit:contain}
.thumb-strip{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:10px}
.thumb-strip a,.thumbs a{display:block}
.thumb-strip .thumb-frame,.thumbs .thumb-frame{aspect-ratio:1/1;padding:8px;border-radius:16px;margin:0}
.path-panel{padding:18px 20px;margin-top:22px}
.breadcrumbs{display:flex;gap:10px;flex-wrap:wrap;font-size:14px;color:var(--muted)}
.page-layout{display:grid;grid-template-columns:minmax(0,1.35fr) 360px;gap:24px;margin-top:24px}
.content-stack{display:grid;gap:18px}
.section-panel{padding:24px}
.section-panel h2,.section-panel h3{margin:0 0 12px;font-family:"Songti SC","STSong","Source Han Serif SC",serif}
.section-panel h2{font-size:30px}
.section-panel h3{font-size:22px}
.bullet-list,.ordered-list{padding-left:20px;margin:0;display:grid;gap:8px}
.muted{color:var(--muted)}
.quote-box{
  padding:18px;border-radius:18px;background:linear-gradient(135deg, rgba(160,79,47,.08), rgba(37,49,66,.05));
  border:1px solid var(--line)
}
.source-grid{display:grid;gap:14px}
.source-item-deep h4{margin:0 0 10px;font-size:18px}
.viewer{padding:18px;position:sticky;top:20px}
.viewer-main .thumb-frame{aspect-ratio:1/1.2}
.viewer-meta{display:grid;gap:12px;margin-top:14px}
.thumbs{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:14px}
.plate-route-group{padding:16px}
.plate-full{width:100%;height:auto;border-radius:18px;border:1px solid var(--line);background:#faf7f0}
.plate-detail-grid{display:grid;grid-template-columns:minmax(0,1.15fr) .85fr;gap:24px;margin-top:20px}
.plate-meta-panel{display:grid;gap:18px}
.glossary-list{display:grid;gap:14px}
.term{font-size:20px;font-family:"Songti SC","STSong","Source Han Serif SC",serif}
.term-en{font-size:13px;text-transform:uppercase;letter-spacing:.08em;color:var(--accent)}
.footer-note{margin-top:36px;color:var(--muted);font-size:13px}
details{border:1px solid var(--line);border-radius:16px;padding:14px 16px;background:#fffdfa}
summary{cursor:pointer;font-weight:600}
@media (max-width:1100px){
  .hero,.page-layout,.plate-detail-grid,.grid-4{grid-template-columns:1fr}
  .grid-3{grid-template-columns:repeat(2,minmax(0,1fr))}
  .viewer{position:static}
}
@media (max-width:720px){
  .page-shell{padding:18px 14px 40px}
  .hero-main h1,.page-title{font-size:38px}
  .grid-3,.grid-2{grid-template-columns:1fr}
  .thumb-strip{grid-template-columns:repeat(3,minmax(0,1fr))}
  .topbar{align-items:flex-start;flex-direction:column}
}