/* 极简知识库样式：系统字体、单栏 780px、黑白灰。 */
:root {
  --fg: #1a1a1a;
  --fg-sub: #666;
  --bg: #fdfdfc;
  --line: #e4e4e0;
  --code-bg: #f4f4f1;
  --link: #0a5a8c;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  display: flex;
  min-height: 100vh;
  font-family: -apple-system, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
  font-size: 16px;
  line-height: 1.8;
  color: var(--fg);
  background: var(--bg);
}

/* ---- 侧边栏（二层菜单）---- */
.sidebar {
  width: 240px;
  flex-shrink: 0;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid var(--line);
  padding: 20px 0 32px;
}

.sidebar-home {
  display: block;
  padding: 6px 20px 14px;
  font-size: 17px;
  font-weight: 600;
  color: var(--fg);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  margin-bottom: 12px;
}

.nav-domain { margin-bottom: 10px; }

.nav-domain-name {
  padding: 4px 20px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-sub);
}

.nav-entry {
  display: block;
  padding: 4px 20px 4px 30px;
  font-size: 14px;
  color: var(--fg);
  text-decoration: none;
  border-left: 3px solid transparent;
}
.nav-entry:hover { background: var(--code-bg); }
.nav-entry.active {
  color: var(--link);
  font-weight: 600;
  border-left-color: var(--link);
  background: var(--code-bg);
}

/* 移动端开关（checkbox hack，无 JS） */
.nav-toggle { display: none; }
.nav-toggle-label {
  display: none;
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 30;
  width: 36px;
  height: 36px;
  line-height: 36px;
  text-align: center;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg);
  cursor: pointer;
  user-select: none;
}

/* ---- 主区 ---- */
.page { flex: 1; min-width: 0; }

.site-header {
  display: flex;
  align-items: baseline;
  gap: 12px;
  max-width: 820px;
  margin: 0 auto;
  padding: 28px 20px 12px;
  border-bottom: 1px solid var(--line);
}

.site-name { font-size: 20px; font-weight: 600; color: var(--fg); text-decoration: none; }
.site-sub { font-size: 13px; color: var(--fg-sub); }

.content {
  max-width: 820px;
  margin: 0 auto;
  padding: 24px 20px 64px;
}

.content h1 { font-size: 26px; margin: 8px 0 16px; line-height: 1.4; }
.content h2 { font-size: 20px; margin: 32px 0 12px; padding-bottom: 6px; border-bottom: 1px solid var(--line); }
.content h3 { font-size: 17px; margin: 24px 0 8px; }

.content a { color: var(--link); text-decoration: none; }
.content a:hover { text-decoration: underline; }

.content table { border-collapse: collapse; width: 100%; margin: 12px 0; font-size: 14px; display: block; overflow-x: auto; }
.content th, .content td { border: 1px solid var(--line); padding: 6px 10px; text-align: left; vertical-align: top; }
.content th { background: var(--code-bg); }

.content code { font-family: Consolas, "JetBrains Mono", monospace; font-size: 0.92em; background: var(--code-bg); padding: 1px 5px; border-radius: 3px; }
.content pre { background: var(--code-bg); padding: 14px; overflow-x: auto; border-radius: 6px; line-height: 1.6; }
.content pre code { background: none; padding: 0; }

.content blockquote { margin: 12px 0; padding: 4px 16px; border-left: 3px solid var(--line); color: var(--fg-sub); }

.content .mermaid { display: flex; justify-content: center; margin: 16px 0; }

.site-footer {
  max-width: 820px;
  margin: 0 auto;
  padding: 16px 20px 40px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--fg-sub);
}
.site-footer a { color: var(--link); text-decoration: none; }

/* ---- 窄屏：侧边栏收成抽屉 ---- */
@media (max-width: 900px) {
  .nav-toggle-label { display: block; }
  .sidebar {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 20;
    width: 260px;
    background: var(--bg);
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.12);
  }
  .nav-toggle:checked ~ .sidebar { display: block; }
  .site-header { padding-left: 56px; }
}