/* orangebook.css — learn-agent-design
   左侧边栏导航 + 右侧本页目录，Claude Code 文档式调性：暖白底、陶土橙强调、克制排版。
   禁 emoji，图标用纯 CSS / line-SVG。 */

:root {
  --brand: #C15F3C;          /* 陶土橙（Anthropic coral 系） */
  --brand-ink: #9E4A2C;
  --brand-soft: #F7ECE6;
  --bg: #ffffff;
  --sidebar-bg: #FAF9F7;
  --ink: #1a1a19;
  --ink-soft: #3d3d3a;
  --muted: #6b6b64;
  --faint: #9a9a92;
  --line: #eae8e3;
  --line-soft: #f2f0ec;
  --code-bg: #f5f4f1;
  --sidebar-w: 300px;
  --radius: 10px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  font-size: 16px; line-height: 1.75; -webkit-font-smoothing: antialiased;
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ============ 布局 ============ */
.layout { display: flex; align-items: flex-start; }
.sidebar {
  width: var(--sidebar-w); flex-shrink: 0;
  position: sticky; top: 0; height: 100vh;
  background: var(--sidebar-bg); border-right: 1px solid var(--line);
}
.sidebar-scroll { height: 100%; overflow-y: auto; padding: 22px 16px 40px; }
.main { flex: 1; min-width: 0; }
.main-inner { max-width: 1220px; margin: 0 auto; padding: 52px 64px 96px; }
.main-inner .content { max-width: 780px; margin: 0 auto; }
.main-inner.with-toc {
  display: grid; grid-template-columns: minmax(0, 760px) 212px;
  gap: 60px; justify-content: center; align-items: start;
}
.main-inner.with-toc .content { max-width: none; margin: 0; }

/* ============ 侧边栏 ============ */
.sidebar-brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 16px; color: var(--ink);
  padding: 6px 10px 18px; border-bottom: 1px solid var(--line); margin-bottom: 14px;
}
.sidebar-brand:hover { text-decoration: none; }
.brand-dot { width: 20px; height: 20px; border-radius: 6px; background: var(--brand); flex-shrink: 0; }
.sidebar-nav { font-size: 14px; }
.nav-section { margin-bottom: 20px; }
.nav-section-title {
  display: flex; align-items: center; gap: 8px;
  font-weight: 600; font-size: 13px; color: var(--ink); letter-spacing: .01em;
  padding: 6px 10px; border-radius: 7px;
}
.nav-section-title:hover { background: rgba(0,0,0,.035); text-decoration: none; }
.nav-section-title.active { color: var(--brand-ink); }
.mod-badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 20px; height: 20px; border-radius: 5px; flex-shrink: 0;
  background: var(--brand); color: #fff; font-size: 11px; font-weight: 700;
}
.nav-section ul { list-style: none; margin: 4px 0 0; padding: 0 0 0 8px; }
.nav-section li { margin: 0; }
.nav-section li a {
  display: block; padding: 6px 12px; margin: 1px 0;
  color: var(--muted); border-radius: 7px; border-left: 2px solid transparent;
  line-height: 1.5; font-size: 13.5px;
}
.nav-section li a:hover { color: var(--ink); background: rgba(0,0,0,.04); text-decoration: none; }
.nav-section li a.active {
  color: var(--brand-ink); font-weight: 600;
  background: var(--brand-soft); border-left-color: var(--brand);
}
.nav-section .soon { color: var(--faint); font-size: 13px; padding: 6px 12px; display: block; }

/* ============ 本页目录 TOC ============ */
.toc { position: sticky; top: 52px; font-size: 13px; }
.toc-title { color: var(--faint); font-weight: 700; letter-spacing: .08em; text-transform: uppercase; font-size: 11px; margin-bottom: 10px; }
.toc ul { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
.toc li a { display: block; padding: 5px 0 5px 14px; margin-left: -1px; color: var(--muted); border-left: 2px solid transparent; line-height: 1.45; }
.toc li a:hover { color: var(--brand-ink); border-left-color: var(--brand); text-decoration: none; }
/* 右栏 TOC 下方的统计（紧凑、可换行） */
.toc .learn-stats { display: block; margin: 26px 0 0; font-size: 12px; line-height: 1.7; padding: 9px 13px; }
/* 模块页/列表页内容底部的统计 */
.content > .learn-stats { margin-top: 36px; }

/* ============ 首页 ============ */
.hero { padding: 18px 0 36px; border-bottom: 1px solid var(--line-soft); margin-bottom: 16px; }
.hero .eyebrow { display: inline-block; font-size: 12px; letter-spacing: .14em; text-transform: uppercase; color: var(--brand); font-weight: 700; margin-bottom: 14px; }
.hero h1 { font-size: 38px; line-height: 1.22; margin: 0 0 16px; letter-spacing: -.015em; font-weight: 700; }
.hero h1 em { font-style: normal; color: var(--brand); }
.hero .lead { font-size: 18px; color: var(--muted); margin: 0; max-width: 620px; }
.learn-stats { margin-top: 20px; display: inline-block; font-size: 14px; color: var(--muted); background: var(--brand-soft); border: 1px solid var(--line); border-radius: 999px; padding: 7px 16px; }
.learn-stats .dot { width: 8px; height: 8px; border-radius: 50%; background: #3f7a5a; box-shadow: 0 0 0 3px rgba(63,122,90,.18); display: inline-block; margin-right: 13px; vertical-align: middle; position: relative; top: -1px; }
.learn-stats strong { color: var(--brand-ink); font-weight: 700; }
.home-sec { display: flex; align-items: center; gap: 10px; font-size: 20px; margin: 40px 0 8px; }
.home-sec .sec-count { margin-left: auto; font-size: 13px; color: var(--faint); font-weight: 500; }
.home-desc { color: var(--muted); margin: 0 0 18px; font-size: 15px; }
.soon-note { color: var(--faint); font-size: 14px; }

/* 模块页头 */
.page-head { padding-bottom: 28px; border-bottom: 1px solid var(--line-soft); margin-bottom: 28px; }
.page-head .mod-badge.big { width: 34px; height: 34px; border-radius: 8px; font-size: 15px; margin-bottom: 14px; }
.page-head h1 { font-size: 32px; margin: 0 0 10px; letter-spacing: -.01em; }
.page-head .lead { color: var(--muted); margin: 0; font-size: 16px; }

/* 模块导语 */
.module-intro { font-size: 16px; color: var(--ink-soft); line-height: 1.85; margin: 0 0 8px; padding: 22px 24px; background: #fbfaf8; border: 1px solid var(--line); border-radius: var(--radius); }
.module-intro p { margin: 0 0 12px; }
.module-intro p:last-child { margin-bottom: 0; }
.module-intro strong { color: var(--ink); }
.list-head { font-size: 14px; font-weight: 700; color: var(--muted); letter-spacing: .04em; margin: 32px 0 14px; }
.mod-badge.ex { background: #3f7a5a; }

/* 讲次卡片（doc 风弱卡片） */
.card-list { display: flex; flex-direction: column; gap: 10px; }
.card {
  display: block; padding: 18px 20px; border: 1px solid var(--line);
  border-radius: var(--radius); background: var(--bg); transition: border-color .15s, background .15s;
}
.card:hover { border-color: var(--brand); background: #fffdfb; text-decoration: none; }
.card-no { font-size: 12px; font-weight: 700; color: var(--brand); letter-spacing: .04em; }
.card h3 { margin: 6px 0 5px; font-size: 17px; color: var(--ink); line-height: 1.45; }
.card p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.6; }

/* ============ 讲义正文 ============ */
.lecture .breadcrumb { font-size: 13px; color: var(--muted); margin-bottom: 16px; display: flex; gap: 8px; align-items: center; }
.lecture .breadcrumb a { color: var(--muted); }
.lecture .breadcrumb span { color: var(--faint); }
.lecture h1 { font-size: 32px; line-height: 1.25; margin: 0 0 12px; letter-spacing: -.015em; }
.lecture .summary {
  font-size: 16.5px; color: var(--ink-soft); margin: 0 0 8px;
  padding: 14px 18px; background: var(--brand-soft); border-radius: var(--radius);
  border-left: 3px solid var(--brand);
}
.lecture .meta { font-size: 13px; color: var(--faint); margin: 0 0 34px; }
.lecture h2 {
  font-size: 23px; margin: 46px 0 14px; padding-top: 22px; line-height: 1.35;
  border-top: 1px solid var(--line-soft); scroll-margin-top: 24px; letter-spacing: -.01em;
}
.lecture h3 { font-size: 18px; margin: 28px 0 10px; }
.lecture p { margin: 14px 0; color: var(--ink-soft); }
.lecture ul, .lecture ol { padding-left: 1.4em; }
.lecture li { margin: 7px 0; color: var(--ink-soft); }
.lecture strong { color: var(--ink); font-weight: 700; }

.lecture blockquote {
  margin: 24px 0; padding: 16px 20px; border-radius: var(--radius);
  background: #fbf7f4; border: 1px solid var(--line); border-left: 3px solid var(--brand);
  font-size: 16.5px; line-height: 1.7; color: var(--brand-ink);
}
.lecture blockquote p { margin: 0; }
.lecture blockquote.callout {
  background: #f6f7f8; border: 1px solid #e6e9ec; border-left: 3px solid #8a93a0;
  color: var(--ink-soft); font-size: 15px;
}
.lecture blockquote.callout::before {
  content: "注"; display: inline-block; margin-right: 10px;
  width: 22px; height: 22px; line-height: 22px; text-align: center;
  border-radius: 6px; background: #6b7280; color: #fff; font-size: 12px; font-weight: 700; vertical-align: 1px;
}
.lecture blockquote.callout-warning { background: #fdf4ee; border-color: #f0d9c8; border-left-color: var(--brand); }
.lecture blockquote.callout-warning::before { content: "警"; background: var(--brand); }
.lecture blockquote.callout-tip::before { content: "提示"; width: auto; padding: 0 8px; background: #3f7a5a; }
.lecture code { background: var(--code-bg); padding: 2px 6px; border-radius: 5px; font-family: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace; font-size: .88em; color: var(--brand-ink); }
.lecture pre { background: #faf9f7; padding: 16px 18px; border-radius: var(--radius); overflow-x: auto; border: 1px solid var(--line); }
.lecture pre code { background: none; padding: 0; color: var(--ink-soft); }

/* 表格（doc 风：浅灰表头，不喧宾夺主） */
.lecture table { width: 100%; border-collapse: collapse; margin: 22px 0; font-size: 14.5px; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.lecture thead th { background: #f7f6f3; color: var(--ink); text-align: left; padding: 11px 14px; font-weight: 600; font-size: 13.5px; border-bottom: 1px solid var(--line); }
.lecture tbody td { padding: 10px 14px; border-top: 1px solid var(--line-soft); vertical-align: top; color: var(--ink-soft); }
.lecture tbody tr:nth-child(even) { background: #fcfbf9; }
.lecture img { max-width: 100%; height: auto; display: block; margin: 24px auto; border-radius: var(--radius); }
.lecture figure.diagram { margin: 28px 0; text-align: center; }
.lecture figure.diagram img { margin: 0 auto; border: 1px solid var(--line); background: #fbfaf8; }
.lecture figure.diagram figcaption { margin-top: 10px; font-size: 13px; color: var(--faint); }

/* 上一讲 / 下一讲 */
.pager { display: flex; justify-content: space-between; gap: 14px; margin-top: 52px; border-top: 1px solid var(--line); padding-top: 22px; }
.pager a { flex: 1; display: flex; flex-direction: column; gap: 4px; padding: 14px 16px; border: 1px solid var(--line); border-radius: var(--radius); color: var(--ink); transition: border-color .15s; }
.pager a:hover { border-color: var(--brand); text-decoration: none; }
.pager a.next { text-align: right; }
.pager .dir { font-size: 12px; color: var(--muted); }
.pager .ttl { font-weight: 600; font-size: 14.5px; }
.pager .spacer { flex: 1; }

/* ============ 响应式 ============ */
@media (max-width: 1080px) {
  .main-inner.with-toc { grid-template-columns: minmax(0, 1fr); }
  .toc { display: none; }
  .main-inner { padding: 44px 40px 80px; }
}
@media (max-width: 820px) {
  .layout { flex-direction: column; }
  .sidebar { position: static; width: 100%; height: auto; border-right: none; border-bottom: 1px solid var(--line); }
  .sidebar-scroll { max-height: 50vh; padding: 16px; }
  .main-inner { padding: 32px 22px 64px; }
  .hero h1 { font-size: 30px; }
  .lecture h1 { font-size: 26px; }
}