/* 教程站点基础样式：书籍式布局（左侧目录 + 右侧正文） */

:root {
  --ink: #1a1a2e;
  --ink-light: #4a4a6a;
  --ink-muted: #6b6b8a;
  --paper: #fafaf9;
  --paper-elevated: #ffffff;
  --accent: #0d9488;
  --accent-hover: #0f766e;
  --border: #e7e5e4;
  --radius: 0px;
  --font-sans: system-ui, -apple-system, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.7;
  font-weight: 400;
}

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

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

/* ---- 书籍式布局：左侧目录 + 右侧正文 ---- */
.book-shell {
  height: 100vh;
  display: grid;
  grid-template-columns: 300px 1fr;
}

.book-sidebar {
  border-right: 1px solid var(--border);
  background: #f7f7f7;
  overflow: auto;
  padding: 12px 0;
}

.book-main {
  overflow: auto;
  padding: 26px 28px;
}

.book-brand {
  padding: 10px 18px 12px;
  font-size: 13px;
  font-weight: 700;
  color: var(--ink);
  border-bottom: 1px solid var(--border);
  margin-bottom: 10px;
}

.book-brand a {
  color: var(--ink);
}

.book-brand a:hover {
  color: var(--accent-hover);
}

.book-nav {
  list-style: none;
  margin: 0;
  padding: 0;
}

.book-nav a {
  display: block;
  padding: 8px 18px;
  color: var(--ink-light);
  text-decoration: none !important;
  font-size: 13px;
}

.book-nav a:hover {
  color: var(--ink);
}

.book-main h1 {
  font-size: 28px;
  font-weight: 700;
  margin: 0 0 14px;
  letter-spacing: -0.01em;
}

.book-main h2 {
  font-size: 18px;
  font-weight: 700;
  margin: 26px 0 12px;
}

.book-main h3 {
  font-size: 15px;
  font-weight: 700;
  margin: 18px 0 8px;
}

.book-main p,
.book-main li {
  color: var(--ink-light);
}

.book-main code {
  background: #f2f2f2;
  border: 1px solid #e5e5e5;
  padding: 0 6px;
  border-radius: 6px;
  color: var(--ink);
  font-size: 0.9em;
}

.book-main pre {
  border: 1px solid #e5e5e5;
  background: #fff;
  padding: 12px;
  overflow: auto;
  margin: 12px 0 16px;
  position: relative;
}

.book-main pre code {
  background: transparent;
  border: 0;
  padding: 0;
}

.book-footer {
  margin-top: 22px;
  font-size: 12px;
  color: var(--ink-muted);
}

.book-footer a {
  color: var(--accent);
}

@media (max-width: 980px) {
  .book-shell {
    grid-template-columns: 1fr;
    height: auto;
  }

  .book-sidebar {
    position: relative;
    max-height: 40vh;
    border-right: 0;
    border-bottom: 1px solid var(--border);
  }

  .book-main {
    overflow: visible;
    padding: 18px 16px;
  }
}