:root {
  --bg: #f7f4ee;
  --panel: #fffdf8;
  --panel-2: #f1eadb;
  --ink: #1d1b18;
  --muted: #6c655d;
  --line: #dbd0c0;
  --brand: #8f3b1b;
  --brand-soft: #f4d8c9;
  --accent: #1f5d57;
  --shadow: 0 12px 30px rgba(55, 35, 12, 0.08);
  --radius: 18px;
  --code: #f4efe6;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "PingFang SC", "Hiragino Sans GB", "Noto Sans CJK SC", "Source Han Sans SC", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(244, 216, 201, 0.55), transparent 28%),
    radial-gradient(circle at top right, rgba(31, 93, 87, 0.08), transparent 24%),
    linear-gradient(180deg, #fbf8f2 0%, #f4efe6 100%);
  line-height: 1.65;
}

a {
  color: var(--brand);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

code {
  background: var(--code);
  padding: 0.16rem 0.4rem;
  border-radius: 8px;
  font-size: 0.92em;
}

pre {
  overflow: auto;
  background: #201d19;
  color: #f7f1e6;
  padding: 1rem 1.1rem;
  border-radius: 14px;
}

.site-shell {
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  margin-bottom: 20px;
  padding: 14px 18px;
  border: 1px solid rgba(143, 59, 27, 0.12);
  background: rgba(255, 253, 248, 0.92);
  backdrop-filter: blur(12px);
  border-radius: 20px;
  box-shadow: var(--shadow);
}

.brand-row {
  display: flex;
  gap: 18px;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  gap: 14px;
  align-items: center;
}

.brand-mark {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  background: linear-gradient(145deg, var(--brand), #cc6b41);
  color: white;
  display: grid;
  place-items: center;
  font-weight: 700;
}

.brand h1 {
  margin: 0;
  font-size: 1.08rem;
}

.brand p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.search-box {
  min-width: 280px;
  flex: 1;
  max-width: 420px;
  position: relative;
}

.search-box input {
  width: 100%;
  padding: 12px 14px;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: #fff;
  font: inherit;
}

.search-results {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  right: 0;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow);
  display: none;
  overflow: hidden;
}

.search-results a {
  display: block;
  padding: 12px 14px;
  border-bottom: 1px solid #efe6da;
  color: var(--ink);
}

.search-results a:last-child {
  border-bottom: 0;
}

.topnav {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 16px;
}

.topnav a {
  padding: 9px 12px;
  border-radius: 999px;
  border: 1px solid transparent;
  color: var(--muted);
}

.topnav a.active {
  color: var(--brand);
  background: var(--brand-soft);
  border-color: rgba(143, 59, 27, 0.15);
  font-weight: 600;
}

.layout {
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  gap: 24px;
}

.sidebar,
.content-card,
.hero,
.callout,
.file-card,
.next-prev {
  border: 1px solid rgba(121, 94, 59, 0.14);
  background: var(--panel);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.sidebar {
  position: sticky;
  top: 118px;
  align-self: start;
  padding: 18px;
}

.sidebar h2 {
  margin-top: 0;
  font-size: 1rem;
}

.sidebar ul {
  margin: 0;
  padding-left: 1rem;
  color: var(--muted);
}

.sidebar li {
  margin: 0.42rem 0;
}

.content {
  min-width: 0;
}

.hero {
  padding: 28px;
  margin-bottom: 20px;
  background:
    linear-gradient(135deg, rgba(143, 59, 27, 0.09), rgba(31, 93, 87, 0.08)),
    var(--panel);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(143, 59, 27, 0.1);
  color: var(--brand);
  font-size: 0.9rem;
  font-weight: 600;
}

.hero h2 {
  margin-bottom: 0.6rem;
  font-size: clamp(1.8rem, 3vw, 2.8rem);
  line-height: 1.15;
}

.hero p {
  max-width: 860px;
  color: #4c473f;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}

.content-card {
  padding: 24px;
  margin-bottom: 18px;
}

.content-card h2 {
  margin-top: 0;
}

.content-card h3 {
  margin-top: 1.6rem;
}

.callout {
  padding: 16px 18px;
  margin: 16px 0;
  background: linear-gradient(180deg, #fff7ef, #fffdf8);
}

.callout strong {
  color: var(--brand);
}

.fact-list,
.check-list {
  padding-left: 1.2rem;
}

.fact-list li,
.check-list li {
  margin: 0.45rem 0;
}

.card-link {
  display: block;
  padding: 18px;
  border-radius: 16px;
  background: var(--panel-2);
  color: var(--ink);
  border: 1px solid rgba(108, 101, 93, 0.12);
}

.card-link strong {
  display: block;
  margin-bottom: 6px;
  color: var(--brand);
}

.file-card {
  padding: 16px 18px;
  margin: 12px 0;
}

.file-card h4 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.file-card p {
  margin: 0;
  color: #504940;
}

.tag-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 12px 0 0;
}

.tag {
  display: inline-flex;
  padding: 5px 10px;
  border-radius: 999px;
  background: #efe6da;
  color: #5f564d;
  font-size: 0.82rem;
}

.next-prev {
  padding: 18px;
  margin-top: 20px;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.next-prev a {
  color: var(--accent);
  font-weight: 600;
}

.question-box {
  padding: 14px 16px;
  border-radius: 14px;
  border: 1px dashed rgba(31, 93, 87, 0.28);
  background: rgba(31, 93, 87, 0.05);
  margin: 12px 0;
}

.diagram-box {
  margin: 16px 0;
  padding: 14px;
  border-radius: 16px;
  border: 1px solid rgba(121, 94, 59, 0.14);
  background: linear-gradient(180deg, #fffaf3, #fffdf8);
  overflow: auto;
}

.diagram-stage {
  min-height: 120px;
}

.diagram-stage .mermaid-host {
  overflow: auto;
}

.diagram-box svg {
  max-width: 100%;
  height: auto;
}

.diagram-note {
  margin: 0.7rem 0 0;
  color: #514b43;
}

.diagram-meta {
  margin-top: 0.9rem;
  padding: 12px 14px;
  border-radius: 14px;
  background: #f7f1e7;
  border: 1px solid rgba(121, 94, 59, 0.12);
}

.diagram-meta strong {
  color: var(--brand);
}

.mermaid-source {
  display: none;
}

.diagram-error {
  margin: 0;
  padding: 14px 16px;
  border-radius: 12px;
  background: #fff3ef;
  border: 1px solid rgba(143, 59, 27, 0.18);
  color: #7a3820;
}

.footer-note {
  color: var(--muted);
  font-size: 0.92rem;
  padding: 12px 0 24px;
}

@media (max-width: 980px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }
}

@media (max-width: 640px) {
  .site-shell {
    padding: 14px;
  }

  .hero,
  .content-card,
  .sidebar {
    padding: 18px;
  }

  .brand-row {
    align-items: stretch;
  }

  .search-box {
    max-width: none;
    min-width: 0;
  }
}