:root {
  --paper: #fbf7ef;
  --ink: #172423;
  --muted: #556665;
  --line: #d9cfbf;
  --shadow: 0 24px 72px rgba(37, 42, 40, 0.08);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(123, 91, 61, 0.13), transparent 28%),
    radial-gradient(circle at top right, rgba(47, 97, 114, 0.11), transparent 30%),
    linear-gradient(180deg, #f3ede0 0%, #f7f2e9 46%, #efe7db 100%);
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.65;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
.top-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.4rem;
  background: rgba(248, 244, 236, 0.86);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(85, 102, 101, 0.14);
}
.brand { font-weight: 700; letter-spacing: 0.04em; }
.route-links { display: flex; flex-wrap: wrap; gap: 0.7rem; }
.route-link {
  padding: 0.55rem 0.88rem;
  border-radius: 999px;
  background: rgba(255,255,255,0.7);
  border: 1px solid rgba(85, 102, 101, 0.12);
  color: var(--muted);
}
.route-link.current { color: var(--ink); background: #fffbf3; }
.page-shell { width: min(1220px, calc(100vw - 2rem)); margin: 0 auto; padding: 1.25rem 0 4rem; }
.hero, .inner-hero {
  display: grid;
  grid-template-columns: 1.45fr 0.95fr;
  gap: 1.35rem;
  padding: 2rem;
  border-radius: 32px;
  background: rgba(252, 249, 242, 0.92);
  border: 1px solid rgba(85, 102, 101, 0.12);
  box-shadow: var(--shadow);
}
.inner-hero { grid-template-columns: 1fr; }
.eyebrow {
  display: inline-flex;
  width: fit-content;
  padding: 0.38rem 0.7rem;
  border-radius: 999px;
  background: #ece1d0;
  color: #73553f;
  font-size: 0.88rem;
  letter-spacing: 0.04em;
}
h1, h2, h3, h4, summary { margin: 0 0 0.75rem; line-height: 1.2; }
h1 { font-size: clamp(2rem, 4vw, 3.6rem); }
h2 { font-size: clamp(1.4rem, 2.5vw, 2rem); }
h3 { font-size: 1.08rem; }
.lead { color: #334442; font-size: 1.08rem; }
.meta-row { display: flex; flex-wrap: wrap; gap: 0.8rem; color: var(--muted); font-size: 0.95rem; }
.thumb-frame {
  height: 100%;
  min-height: 250px;
  display: grid;
  place-items: center;
  padding: 1rem;
  border-radius: 26px;
  background: linear-gradient(180deg, #f6f0e5 0%, #ece4d6 100%);
  border: 1px solid rgba(85, 102, 101, 0.12);
}
.thumb-frame img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  border-radius: 18px;
  background: #fffdf8;
  box-shadow: inset 0 0 0 1px rgba(85, 102, 101, 0.08);
}
.track-grid, .card-grid, .route-grid, .mini-grid, .glossary-grid, .deep-grid, .content-grid {
  display: grid;
  gap: 1rem;
}
.track-grid { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); margin: 1.4rem 0 2rem; }
.track-card, .section-block, .chapter-card, .concept-card, .plate-card, .route-card, .sidebar-group, .glossary-card, .deep-card {
  border-radius: 26px;
  background: rgba(252, 249, 243, 0.94);
  border: 1px solid rgba(85, 102, 101, 0.1);
  box-shadow: var(--shadow);
}
.track-card { padding: 1.35rem; border-top: 6px solid var(--track); }
.track-meta, .section-head p, .card-copy p, .route-card p, .sidebar-group p, .term-en, .deep-label { color: var(--muted); }
.section-block { padding: 1.4rem; }
.section-head { display: flex; flex-direction: column; gap: 0.35rem; margin-bottom: 1rem; }
.chapters-grid { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.concepts-grid { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.plates-grid { grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); }
.glossary-grid { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.deep-grid { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.card-link { display: block; height: 100%; }
.card-copy { padding: 1rem 1rem 1.1rem; }
.badge {
  display: inline-block;
  margin-bottom: 0.7rem;
  padding: 0.26rem 0.6rem;
  border-radius: 999px;
  color: #fff9ef;
  background: var(--badge);
  font-size: 0.82rem;
}
.concept-chip {
  display: inline-flex;
  margin: 1rem 1rem 0;
  padding: 0.34rem 0.62rem;
  border-radius: 999px;
  background: #ece1d0;
  color: #6f563f;
  font-size: 0.82rem;
}
.content-grid { grid-template-columns: minmax(0, 1.5fr) minmax(300px, 0.86fr); align-items: start; }
.main-column, .side-column { display: grid; gap: 1rem; }
.route-grid { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.mini-grid { grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); }
.route-card, .deep-card, .glossary-card { padding: 1rem; }
.plate-mini { display: grid; gap: 0.5rem; font-size: 0.9rem; }
.plate-mini span { color: var(--muted); }
.bullet-list { margin: 0; padding-left: 1.15rem; }
.bullet-list li + li { margin-top: 0.5rem; }
.qa-box {
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: #f6efe1;
  border: 1px solid rgba(85, 102, 101, 0.1);
}
.qa-box summary { cursor: pointer; font-weight: 700; }
.qa-box p { margin: 0.85rem 0 0; }
.path-panel {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: #f0e7d8;
}
.path-panel a { color: #355f73; }
.intro-note {
  padding: 1rem 1.15rem;
  border-radius: 22px;
  background: #f4ecde;
  color: #4d5b58;
}
.plate-figure {
  margin: 0;
  padding: 1rem;
  border-radius: 28px;
  background: rgba(252, 249, 243, 0.94);
  border: 1px solid rgba(85, 102, 101, 0.1);
  box-shadow: var(--shadow);
}
.plate-figure img {
  width: 100%;
  border-radius: 16px;
  background: #fffdf8;
}
.search-input {
  width: 100%;
  margin-top: 0.8rem;
  padding: 0.95rem 1rem;
  border-radius: 16px;
  border: 1px solid rgba(85, 102, 101, 0.15);
  background: #fffdf8;
  font: inherit;
}
@media (max-width: 960px) {
  .hero, .content-grid { grid-template-columns: 1fr; }
  .page-shell { width: min(100vw - 1rem, 1220px); }
}