:root{
  --bg:#efe7da;
  --paper:#fffdf9;
  --ink:#222e38;
  --muted:#667483;
  --line:#d8cdbb;
  --navy:#17364b;
  --rust:#8c4d2f;
  --gold:#b48439;
  --sea:#dfeaf0;
  --sand:#f3ecdf;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:
linear-gradient(180deg,rgba(239,231,218,.97),rgba(239,231,218,.97)),
radial-gradient(circle at 16% 0%,rgba(23,54,75,.10),transparent 30%),
radial-gradient(circle at 84% 10%,rgba(180,132,57,.10),transparent 28%),
linear-gradient(135deg,rgba(255,255,255,.25),rgba(255,255,255,0));
color:var(--ink);font-family:"Source Han Serif SC","Songti SC","Noto Serif CJK SC",serif;line-height:1.8}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.topbar{position:sticky;top:0;z-index:10;display:flex;justify-content:space-between;align-items:center;padding:16px 5vw;background:rgba(239,231,218,.9);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.brand{font-family:"Avenir Next","PingFang SC",sans-serif;font-weight:800;letter-spacing:.08em}
.topbar nav{display:flex;gap:18px;font-family:"Avenir Next","PingFang SC",sans-serif;font-size:14px;color:var(--muted)}
main{width:min(1200px,92vw);margin:0 auto;padding:42px 0 72px}
.hero{display:grid;grid-template-columns:1.3fr .8fr;gap:28px;align-items:stretch;padding:46px 0 18px}
.hero h1{font-size:clamp(50px,7.4vw,88px);line-height:.92;margin:12px 0}
.lead{font-size:20px;color:#4c5864;max-width:820px}
.eyebrow{font-family:"Avenir Next","PingFang SC",sans-serif;font-size:12px;text-transform:uppercase;letter-spacing:.18em;color:var(--gold);font-weight:800}
.hero-copy,.hero-panel,.panel,.card,.deep-card,.sidebar,.viewer-panel,.viewer-figure,.answer-panel,.plate-detail,table{background:var(--paper);border:1px solid var(--line);border-radius:26px;box-shadow:0 18px 60px rgba(34,46,56,.06)}
.hero-copy{padding:32px}
.hero-panel,.panel,.sidebar,.viewer-panel{padding:24px}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin:20px 0 28px}
.button{display:inline-flex;align-items:center;justify-content:center;padding:13px 18px;border-radius:999px;background:var(--navy);color:#fff;font-family:"Avenir Next","PingFang SC",sans-serif;font-weight:700}
.button.secondary{background:transparent;color:var(--navy);border:1px solid var(--navy)}
.hero-notes{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}
.hero-notes div{padding:14px 16px;border-radius:18px;background:var(--sea)}
.hero-notes strong{display:block;font-size:28px;color:var(--navy);font-family:"Avenir Next",sans-serif}
.hero-notes span{font-family:"Avenir Next","PingFang SC",sans-serif;font-size:13px;color:var(--muted)}
.cover-frame{margin:0 0 18px}
.cover-frame img{width:100%;aspect-ratio:4/5;object-fit:contain;background:var(--sand);border-radius:18px;padding:16px}
section{margin:34px 0}
h1,h2,h3{line-height:1.18}
h2{font-size:28px;margin:0 0 14px}
.route-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:12px}
.route-grid div{padding:18px;border-radius:18px;background:linear-gradient(135deg,#e5eef3,#f8f1e6);border:1px solid var(--line);text-align:center;font-weight:700}
.grid{display:grid;gap:18px}
.chapter-grid{grid-template-columns:repeat(3,1fr)}
.concept-grid{grid-template-columns:repeat(4,1fr)}
.card{display:block;padding:22px;transition:transform .18s ease,box-shadow .18s ease}
.card:hover,.mini-plate:hover,.side-plate:hover,.thumb-button:hover{transform:translateY(-2px);box-shadow:0 20px 60px rgba(34,46,56,.10)}
.card-cover{margin:-4px -4px 16px}
.card-cover img,.plate-card img,.plate-mini img,.mini-plate img,.side-plate img,.thumb-button img{width:100%;aspect-ratio:4/3;object-fit:contain;background:var(--sand);border-radius:18px;padding:10px}
.chapter-card small,.plate-meta,.filter-group,.thumb-button span,.mini-plate span,.plate-mini span,.side-plate span{font-family:"Avenir Next","PingFang SC",sans-serif;color:var(--muted)}
.plate-band{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.plate-mini,.mini-plate,.side-plate{display:block;padding:10px;border-radius:18px;border:1px solid var(--line);background:var(--paper)}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 330px;gap:28px}
.tag-row{display:flex;flex-wrap:wrap;gap:10px}
.tag{display:inline-flex;padding:8px 12px;border-radius:999px;background:#edf1f3;color:#20465f;font-family:"Avenir Next","PingFang SC",sans-serif;font-size:14px}
.deep-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}
.deep-card{padding:22px}
.deep-card blockquote{margin:14px 0 0;padding-left:14px;border-left:4px solid var(--gold);color:#586570}
.sidebar{position:sticky;top:86px;align-self:start}
.two{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}
.path{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}
.path a{padding:10px 14px;border-radius:16px;background:#edf1f3;color:#20465f;font-family:"Avenir Next","PingFang SC",sans-serif}
.mini-plate-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}
.viewer-panel h2{margin-top:0}
.viewer-figure{margin:0;padding:14px}
.viewer-main{width:100%;aspect-ratio:4/3;object-fit:contain;background:var(--sand);border-radius:18px;padding:10px}
.viewer-figure figcaption{margin-top:10px;color:var(--muted);font-family:"Avenir Next","PingFang SC",sans-serif}
.thumb-strip{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin-top:14px}
.thumb-button{display:flex;flex-direction:column;gap:8px;padding:10px;border-radius:18px;border:1px solid var(--line);background:var(--paper);cursor:pointer;transition:transform .18s ease,box-shadow .18s ease}
.thumb-button.is-active{outline:2px solid rgba(23,54,75,.42)}
.answer-button{display:block;width:100%;padding:14px 16px;border-radius:18px;border:1px solid var(--line);background:#eef2f4;color:#20465f;text-align:left;font:inherit;cursor:pointer}
.answer-panel{margin-top:12px;padding:18px}
.plate-grid{grid-template-columns:repeat(4,1fr)}
.plate-card{padding:14px}
.plate-meta{display:flex;justify-content:space-between;gap:8px;font-size:12px;margin-top:10px}
.plate-detail{padding:18px}
.full-plate{width:100%;max-height:700px;object-fit:contain;background:var(--sand);border-radius:18px;padding:10px}
.filter-row{display:grid;gap:14px;margin:20px 0}
.filter-group{display:flex;flex-wrap:wrap;gap:10px;align-items:center}
.filter-group span{font-size:13px;letter-spacing:.02em}
.filter-button{padding:9px 12px;border-radius:999px;border:1px solid var(--line);background:var(--paper);color:#4d6472;cursor:pointer;font-family:"Avenir Next","PingFang SC",sans-serif}
.filter-button.is-active{background:var(--navy);color:#fff;border-color:var(--navy)}
.side-plate-grid{display:grid;gap:12px}
table{width:100%;border-collapse:collapse;overflow:hidden}
th,td{padding:16px;border-bottom:1px solid var(--line);text-align:left}
th{background:#efe7da;font-family:"Avenir Next","PingFang SC",sans-serif}
@media (max-width:980px){
  .hero,.layout{grid-template-columns:1fr}
  .chapter-grid,.concept-grid,.plate-grid,.deep-grid,.two,.mini-plate-grid{grid-template-columns:1fr}
  .plate-band,.route-grid,.thumb-strip{grid-template-columns:repeat(2,1fr)}
  .sidebar{position:static}
}
@media (max-width:700px){
  .topbar{flex-direction:column;align-items:flex-start;gap:10px}
  .hero-notes{grid-template-columns:1fr}
  .plate-band,.route-grid,.thumb-strip{grid-template-columns:1fr}
}