:root {
  --paper: #faf8f3;
  --paper-deep: #f3efe6;
  --ink: #1c1a17;
  --muted: #6f6a61;
  --line: #e5dfd2;
  --accent: #b03a32;
  --accent-soft: #f7e8e6;
  --card: #ffffff;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: "Zen Kaku Gothic New", "Hiragino Kaku Gothic ProN", sans-serif;
  line-height: 1.9;
  overflow-x: hidden;
  -webkit-text-size-adjust: 100%;
}
h1, h2, h3, .brand strong { font-family: "Shippori Mincho", serif; }

/* 顶栏 */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 16px;
  padding: 12px 24px;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.brand-mark {
  width: 36px; height: 36px; border-radius: 8px;
  background: var(--accent); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-family: "Shippori Mincho", serif; font-size: 20px; font-weight: 700;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.3; }
.brand-text strong { font-size: 18px; letter-spacing: 2px; }
.brand-text small { font-size: 11px; color: var(--muted); }
.lang-switch { margin-left: auto; display: flex; gap: 4px; }
.lang-switch button {
  border: 1px solid var(--line); background: transparent; color: var(--muted);
  border-radius: 20px; padding: 5px 14px; font-size: 13px; cursor: pointer;
}
.lang-switch button.active { background: var(--ink); color: #fff; border-color: var(--ink); }
.menu-btn {
  display: none; border: 1px solid var(--line); background: transparent;
  border-radius: 8px; font-size: 18px; padding: 4px 12px; cursor: pointer; color: var(--ink);
}

/* 布局 */
.layout { display: flex; max-width: 1200px; margin: 0 auto; min-height: calc(100vh - 61px); }
.sidebar {
  width: 280px; flex-shrink: 0;
  border-right: 1px solid var(--line);
  padding: 24px 16px;
  position: sticky; top: 61px; height: calc(100vh - 61px); overflow-y: auto;
  background: var(--paper);
}
.nav-group { margin-bottom: 20px; }
.nav-group h4 {
  font-size: 12px; color: var(--muted); letter-spacing: 2px;
  margin: 0 0 8px 8px; font-weight: 700;
  border-left: 3px solid var(--accent); padding-left: 8px;
}
.nav-group a {
  display: block; padding: 7px 12px; border-radius: 8px;
  color: var(--ink); text-decoration: none; font-size: 14px; line-height: 1.6;
}
.nav-group a:hover { background: var(--paper-deep); }
.nav-group a.active { background: var(--accent-soft); color: var(--accent); font-weight: 700; }
.side-foot { margin-top: 24px; padding-top: 16px; border-top: 1px solid var(--line); }
.side-foot a { color: var(--accent); font-size: 13px; text-decoration: none; font-weight: 700; }

/* 正文 */
.content { flex: 1; min-width: 0; padding: 36px 48px 80px; }
.content h1 { font-size: 30px; margin: 0 0 8px; line-height: 1.5; }
.stage-badge {
  display: inline-block; font-size: 12px; font-weight: 700;
  color: var(--accent); background: var(--accent-soft);
  border-radius: 20px; padding: 3px 14px; margin-bottom: 16px; letter-spacing: 1px;
}
.toc {
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  padding: 16px 20px; margin: 0 0 28px;
}
.toc strong { font-size: 13px; color: var(--muted); letter-spacing: 1px; }
.toc ul { margin: 8px 0 0; padding-left: 20px; font-size: 14px; }
.toc a { color: var(--ink); text-decoration: none; }
.toc a:hover { color: var(--accent); }
.content h3 {
  font-size: 20px; margin: 36px 0 12px; padding-bottom: 8px;
  border-bottom: 2px solid var(--line);
}
.content p { margin: 12px 0; }
.content ul, .content ol { padding-left: 24px; margin: 12px 0; }
.content li { margin: 6px 0; }
.content li::marker { color: var(--accent); font-weight: 700; }
.content code {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  background: var(--paper-deep); border-radius: 4px; padding: 1px 6px; font-size: 0.9em;
}
.content pre {
  background: #232019; color: #f0e9da; border-radius: 10px;
  padding: 16px 20px; overflow-x: auto; font-size: 13px; line-height: 1.7;
}
.content pre code { background: none; padding: 0; color: inherit; }
.content table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 14px; display: block; overflow-x: auto; }
.content th, .content td { border: 1px solid var(--line); padding: 8px 12px; text-align: left; white-space: nowrap; }
.content th { background: var(--paper-deep); }
.content a { color: var(--accent); }
.content strong { color: var(--ink); }

/* 首页卡片 */
.hero h1 { font-size: 34px; }
.hero p.lead { color: var(--muted); font-size: 16px; max-width: 640px; }
.stage-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 28px 0; }
.stage-card {
  background: var(--card); border: 1px solid var(--line); border-radius: 14px;
  padding: 20px; text-decoration: none; color: var(--ink);
}
.stage-card:hover { border-color: var(--accent); }
.stage-card .num {
  font-family: "Shippori Mincho", serif; font-size: 28px; color: var(--accent); font-weight: 700;
}
.stage-card h2 { font-size: 18px; margin: 8px 0 4px; }
.stage-card p { font-size: 13px; color: var(--muted); margin: 0; }
.all-list { columns: 2; column-gap: 32px; }
.all-list a { display: block; padding: 6px 0; color: var(--ink); text-decoration: none; font-size: 14px; break-inside: avoid; }
.all-list a:hover { color: var(--accent); }
.all-list .no { color: var(--muted); font-size: 12px; margin-right: 8px; }

/* 移动端 */
@media (max-width: 900px) {
  .sidebar {
    position: fixed; left: 0; top: 61px; bottom: 0; z-index: 40;
    transform: translateX(-100%); transition: transform 0.25s ease;
    width: 260px; box-shadow: 4px 0 24px rgba(0,0,0,0.08);
    height: calc(100vh - 61px);
  }
  .sidebar.open { transform: none; }
  .menu-btn { display: block; }
  .content { padding: 24px 20px 64px; }
  .stage-cards { grid-template-columns: 1fr; }
  .all-list { columns: 1; }
  .topbar { padding: 10px 16px; gap: 10px; }
  .lang-switch button { padding: 4px 10px; font-size: 12px; }
}