:root {
  --paper: #faf7f1;
  --paper-2: #f2ede3;
  --ink: #1c1a17;
  --ink-2: #4a453d;
  --ink-3: #7d766a;
  --line: #e0d8c9;
  --accent: #a5432a;
  --accent-soft: rgba(165, 67, 42, 0.08);
  --code-bg: #f1ece1;
  --shadow: 0 1px 2px rgba(28, 26, 23, 0.05);
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC", Georgia, serif;
  --sans: "Optima", "Avenir Next", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --nav-w: 264px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #16150f;
    --paper-2: #1e1c15;
    --ink: #e9e3d6;
    --ink-2: #b8b1a2;
    --ink-3: #857e70;
    --line: #302c22;
    --accent: #d97a55;
    --accent-soft: rgba(217, 122, 85, 0.12);
    --code-bg: #201d15;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ---------- 顶栏 ---------- */
.topbar {
  display: none;
  position: sticky;
  top: 0;
  z-index: 40;
  align-items: center;
  gap: 12px;
  padding: 12px 18px;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.topbar__title {
  font-family: var(--serif);
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.topbar__toggle {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  font: inherit;
  font-size: 13px;
  color: var(--ink-2);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 999px;
  cursor: pointer;
}

.topbar__toggle:hover { border-color: var(--ink-3); color: var(--ink); }

/* ---------- 布局 ---------- */
.layout {
  display: grid;
  grid-template-columns: var(--nav-w) minmax(0, 1fr);
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 32px;
}

/* ---------- 侧栏 ---------- */
.side {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 44px 28px 28px 0;
  border-right: 1px solid var(--line);
}

.brand { margin-bottom: 30px; }

.brand__mark {
  display: inline-block;
  font-family: var(--serif);
  font-size: 20px;
  letter-spacing: 0.01em;
  color: var(--ink);
  text-decoration: none;
}

.brand__mark span { color: var(--accent); }

.brand__sub {
  margin: 6px 0 0;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--ink-3);
  text-transform: uppercase;
}

.nav {
  flex: 1;
  overflow-y: auto;
  margin: 0 -8px;
  padding: 0 8px;
  scrollbar-width: thin;
}

.nav::-webkit-scrollbar { width: 4px; }
.nav::-webkit-scrollbar-thumb { background: var(--line); border-radius: 4px; }

.nav__group {
  margin: 0 0 22px;
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ink-3);
  text-transform: uppercase;
}

.nav a {
  display: flex;
  gap: 10px;
  padding: 5px 0 5px 10px;
  font-size: 15px;
  color: var(--ink-2);
  text-decoration: none;
  border-left: 1px solid var(--line);
  transition: color 0.15s ease, border-color 0.15s ease;
}

.nav a .num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-3);
  padding-top: 3px;
  min-width: 18px;
}

.nav a:hover { color: var(--ink); border-left-color: var(--ink-3); }

.nav a.is-active {
  color: var(--accent);
  border-left-color: var(--accent);
  font-weight: 600;
}

.nav a.is-active .num { color: var(--accent); }

.side__meta {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  line-height: 1.9;
  color: var(--ink-3);
}

/* ---------- 正文 ---------- */
.main {
  min-width: 0;
  padding: 56px 0 120px 56px;
}

.doc { max-width: 720px; overflow-wrap: break-word; }

.doc__eyebrow {
  margin: 0 0 14px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--accent);
}

.doc h1 {
  margin: 0 0 18px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(30px, 4vw, 42px);
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.doc__lede {
  margin: 0 0 26px;
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink-2);
}

.doc__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin: 0 0 44px;
  padding: 14px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-3);
}

.doc__meta b { font-weight: 600; color: var(--ink-2); }

section { scroll-margin-top: 24px; }

.doc h2 {
  margin: 64px 0 18px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 26px;
  line-height: 1.35;
  scroll-margin-top: 24px;
}

/* 章节编号作为标题上方的引导标记 */
.doc h2 .idx {
  display: block;
  margin: 0 0 4px;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.1em;
  color: var(--accent);
}

.doc h3 {
  margin: 34px 0 10px;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.5;
}

.doc p { margin: 0 0 16px; }

.doc a { color: var(--accent); text-decoration: none; border-bottom: 1px solid var(--accent-soft); }
.doc a:hover { border-bottom-color: var(--accent); }

.doc ul, .doc ol { margin: 0 0 18px; padding-left: 22px; }
.doc li { margin: 6px 0; }
.doc li::marker { color: var(--ink-3); }

.doc code {
  font-family: var(--mono);
  font-size: 0.875em;
  padding: 1px 5px;
  border-radius: 3px;
  background: var(--code-bg);
  color: var(--ink);
}

.doc pre {
  position: relative;
  margin: 0 0 20px;
  padding: 18px 20px;
  overflow-x: auto;
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-left: 2px solid var(--accent);
  border-radius: 4px;
  font-size: 14px;
  line-height: 1.7;
}

.doc pre code {
  padding: 0;
  background: none;
  font-size: inherit;
  white-space: pre;
}

.doc pre .c { color: var(--ink-3); }

.copy {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 3px 9px;
  font: inherit;
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--ink-3);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 3px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s ease, color 0.15s ease;
}

.doc pre:hover .copy, .copy:focus-visible { opacity: 1; }
.copy:hover { color: var(--accent); border-color: var(--accent); }
.copy.is-done { color: var(--accent); opacity: 1; }

.note {
  margin: 0 0 20px;
  padding: 14px 18px;
  background: var(--accent-soft);
  border-left: 2px solid var(--accent);
  border-radius: 0 4px 4px 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-2);
}

.note b { color: var(--ink); }
.note p:last-child { margin-bottom: 0; }

table {
  width: 100%;
  margin: 0 0 22px;
  border-collapse: collapse;
  font-size: 15px;
}

/* 表格外层滚动容器：窄屏横向滚动，不撑破页面 */
.table-wrap {
  margin: 0 0 22px;
  overflow-x: auto;
  overscroll-behavior-x: contain;
  -webkit-overflow-scrolling: touch;
}

.table-wrap table { margin-bottom: 0; }

th, td {
  padding: 9px 12px;
  text-align: left;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

th {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--ink-3);
  text-transform: uppercase;
  border-bottom-color: var(--ink-3);
}

td code { white-space: nowrap; }

hr.rule {
  margin: 56px 0;
  border: 0;
  border-top: 1px solid var(--line);
}

footer.doc__foot {
  margin-top: 72px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-3);
}

/* ---------- 进度条 ---------- */
.progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0;
  background: var(--accent);
  z-index: 60;
  transition: width 0.1s linear;
}

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .topbar { display: flex; }
  .progress { top: 0; }

  .layout {
    display: block;
    padding: 0 22px;
  }

  .side {
    position: fixed;
    top: 0;
    left: 0;
    z-index: 50;
    width: min(82vw, 320px);
    height: 100vh;
    padding: 24px 22px;
    background: var(--paper);
    border-right: 1px solid var(--line);
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.16);
    transform: translateX(-102%);
    transition: transform 0.24s ease;
    overflow-y: auto;
  }

  .side.is-open { transform: translateX(0); }

  .brand { margin-bottom: 22px; }
  .nav { overflow: visible; }

  .main { padding: 34px 0 90px; }
  .doc h2 { margin-top: 52px; }

  .scrim {
    position: fixed;
    inset: 0;
    z-index: 45;
    background: rgba(20, 18, 14, 0.36);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.24s ease;
  }

  .scrim.is-on { opacity: 1; pointer-events: auto; }
}

@media (min-width: 961px) {
  .scrim { display: none; }
}

@media (max-width: 560px) {
  body { font-size: 16px; }
  .doc h1 { font-size: 28px; }
  .doc h2 { font-size: 23px; }
  .doc__lede { font-size: 17px; }
  .doc pre { margin-left: -8px; margin-right: -8px; border-radius: 3px; }
  table { font-size: 14px; }
  th, td { padding: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; animation: none !important; }
}

@media print {
  .side, .topbar, .progress, .copy, .scrim { display: none !important; }
  .layout { display: block; padding: 0; }
  .main { padding: 0; }
  .doc { max-width: none; }
  .doc pre { border: 1px solid #ccc; }
}


/* ---------- 教程切换（侧栏） ---------- */
.side__group {
  margin: 0 0 8px;
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ink-3);
  text-transform: uppercase;
}

.tut-nav { margin-bottom: 26px; }

.tut-nav a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 6px 10px;
  margin-bottom: 2px;
  font-size: 15px;
  color: var(--ink-2);
  text-decoration: none;
  border-radius: 4px;
  transition: background 0.15s ease, color 0.15s ease;
}

.tut-nav a:hover { background: var(--paper-2); color: var(--ink); }

.tut-nav a.is-here {
  color: var(--accent);
  background: var(--accent-soft);
  font-weight: 600;
}

.tut-nav a .dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--line);
  flex: none;
  transform: translateY(-3px);
}

.tut-nav a.is-here .dot { background: var(--accent); }

.tut-nav a.soon { color: var(--ink-3); cursor: default; }
.tut-nav a.soon:hover { background: none; }

/* ---------- 面包屑 ---------- */
.crumbs {
  margin: 0 0 18px;
  font-size: 13px;
  color: var(--ink-3);
  letter-spacing: 0.02em;
}

.crumbs a { color: var(--ink-3); text-decoration: none; border-bottom: 1px solid transparent; }
.crumbs a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.crumbs span { color: var(--ink-2); }

/* ---------- 首页 ---------- */
.layout--home {
  display: block;
  max-width: 1080px;
  padding: 0 32px;
}

.home { padding: 84px 0 120px; max-width: 900px; }

.home__eyebrow {
  margin: 0 0 18px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--accent);
}

.home h1 {
  margin: 0 0 20px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(32px, 5vw, 52px);
  line-height: 1.22;
  letter-spacing: -0.015em;
}

.home__lede {
  max-width: 620px;
  margin: 0 0 56px;
  font-size: 17.5px;
  line-height: 1.9;
  color: var(--ink-2);
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(236px, 1fr));
  gap: 12px;
  margin: 0 0 44px;
  padding: 0;
  list-style: none;
}

.card {
  display: flex;
  flex-direction: column;
  padding: 16px 18px 14px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 6px;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(28, 26, 23, 0.06);
}

.card__tag {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 6px;
}

.card h2 {
  margin: 0 0 6px;
  line-height: 1.35;
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 600;
  letter-spacing: 0;
}

.card p {
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink-2);
}

.card__meta {
  margin-top: auto;
  display: flex;
  gap: 12px;
  font-size: 13px;
  color: var(--ink-3);
}

.card--soon {
  border-style: dashed;
  background: transparent;
  color: var(--ink-3);
}

.home__note {
  max-width: 620px;
  padding: 16px 18px;
  border-left: 2px solid var(--accent);
  background: var(--accent-soft);
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-2);
}

@media (max-width: 960px) {
  .layout--home { padding: 0 22px; }
  .home { padding: 44px 0 80px; }
  .home__lede { margin-bottom: 36px; font-size: 16px; }
  .cards { gap: 10px; margin-bottom: 32px; }
  .card { padding: 14px 16px 12px; }
}


/* ---------- 首页卡片分组 ---------- */
.cards__group {
  grid-column: 1 / -1;
  margin: 8px 0 -2px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-3);
  text-transform: uppercase;
  list-style: none;
}

.cards__group:first-child { margin-top: 0; }

.side__group--sub {
  margin: 14px 0 6px;
  padding-left: 10px;
  font-size: 10.5px;
  letter-spacing: 0.14em;
}

.tut-nav .side__group:first-child { margin-top: 0; }