/* ===== 随时读 使用文档 - 白色主题样式表 ===== */
:root {
  --primary: #2563EB;
  --primary-light: #3B82F6;
  --primary-dark: #1D4ED8;
  --accent: #F97316;
  --success: #16A34A;
  --danger: #DC2626;
  
  --bg: #FFFFFF;
  --bg-secondary: #F8FAFC;
  --bg-tertiary: #F1F5F9;
  --text: #0F172A;
  --text-secondary: #475569;
  --text-tertiary: #94A3B8;
  --border: #E2E8F0;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --radius: 8px;
  --radius-lg: 12px;
  --max-width: 960px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 15px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

.top-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.top-nav .logo { font-size: 18px; font-weight: 700; color: var(--primary); text-decoration: none; display: flex; align-items: center; gap: 8px; }
.top-nav .logo span { color: var(--text); font-weight: 600; }
.top-nav .nav-links { display: flex; gap: 4px; list-style: none; }
.top-nav .nav-links a { padding: 6px 12px; font-size: 13px; color: var(--text-secondary); text-decoration: none; border-radius: var(--radius); transition: all 0.2s; }
.top-nav .nav-links a:hover, .top-nav .nav-links a.active { color: var(--primary); background: var(--bg-tertiary); }

.sidebar { position: fixed; top: 56px; left: 0; bottom: 0; width: 240px; overflow-y: auto; border-right: 1px solid var(--border); background: var(--bg); padding: 16px 0; }
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }
.sidebar-section { margin-bottom: 8px; }
.sidebar-section .section-title { padding: 6px 20px; font-size: 11px; font-weight: 600; color: var(--text-tertiary); text-transform: uppercase; letter-spacing: 0.5px; }
.sidebar-section a { display: block; padding: 7px 20px 7px 24px; font-size: 14px; color: var(--text-secondary); text-decoration: none; border-left: 3px solid transparent; transition: all 0.15s; }
.sidebar-section a:hover { color: var(--primary); background: var(--bg-secondary); }
.sidebar-section a.active { color: var(--primary); background: #EFF6FF; border-left-color: var(--primary); font-weight: 600; }

.main-content { margin-left: 240px; margin-top: 56px; padding: 40px 48px 80px; max-width: var(--max-width); }
.main-content.full-width { max-width: 100%; padding: 40px 48px 80px; }

.hero { text-align: center; padding: 60px 0 48px; }
.hero h1 { font-size: 36px; font-weight: 800; color: var(--text); margin-bottom: 12px; }
.hero p { font-size: 17px; color: var(--text-secondary); max-width: 600px; margin: 0 auto 32px; }

.feature-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 20px; margin: 40px 0; }
.feature-card { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 24px; transition: all 0.2s; }
.feature-card:hover { border-color: var(--primary-light); box-shadow: var(--shadow-md); transform: translateY(-2px); }
.feature-card .icon { width: 40px; height: 40px; border-radius: 10px; display: flex; align-items: center; justify-content: center; font-size: 20px; margin-bottom: 14px; }
.feature-card h3 { font-size: 16px; font-weight: 600; margin-bottom: 6px; }
.feature-card p { font-size: 13px; color: var(--text-secondary); line-height: 1.6; }

h1 { font-size: 30px; font-weight: 800; margin: 0 0 8px; }
h2 { font-size: 22px; font-weight: 700; margin: 40px 0 12px; padding-bottom: 8px; border-bottom: 2px solid var(--border); }
h3 { font-size: 17px; font-weight: 600; margin: 28px 0 8px; }
h4 { font-size: 15px; font-weight: 600; margin: 20px 0 6px; }
p { margin-bottom: 14px; color: var(--text-secondary); }
ul, ol { margin: 0 0 14px 20px; }
li { margin-bottom: 6px; color: var(--text-secondary); }

code { font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace; font-size: 13px; background: var(--bg-tertiary); padding: 2px 6px; border-radius: 4px; color: var(--text); }

.tip, .info, .warning, .note { padding: 14px 18px; border-radius: var(--radius); margin: 20px 0; font-size: 14px; line-height: 1.6; border-left: 4px solid; }
.tip { background: #F0FDF4; border-color: var(--success); color: #166534; }
.info { background: #EFF6FF; border-color: var(--primary); color: #1E40AF; }
.warning { background: #FFF7ED; border-color: var(--accent); color: #9A3412; }

.steps { counter-reset: step; list-style: none; margin: 20px 0; padding: 0; }
.steps li { counter-increment: step; padding: 16px 20px 16px 52px; position: relative; background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); margin-bottom: 10px; color: var(--text-secondary); }
.steps li::before { content: counter(step); position: absolute; left: 16px; top: 16px; width: 26px; height: 26px; background: var(--primary); color: #fff; font-size: 13px; font-weight: 700; display: flex; align-items: center; justify-content: center; border-radius: 50%; }
.steps li strong { color: var(--text); }

table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 14px; }
th, td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); }
th { background: var(--bg-secondary); font-weight: 600; color: var(--text); font-size: 13px; }
tr:hover td { background: var(--bg-secondary); }

.tag { display: inline-block; padding: 2px 8px; font-size: 11px; font-weight: 600; border-radius: 10px; margin-right: 4px; }
.tag-pro { background: #FEF3C7; color: #92400E; }
.tag-free { background: #DBEAFE; color: #1E40AF; }

.page-footer { margin-top: 60px; padding-top: 24px; border-top: 1px solid var(--border); display: flex; justify-content: space-between; }
.page-footer a { color: var(--primary); text-decoration: none; font-size: 14px; font-weight: 500; }
.page-footer a:hover { text-decoration: underline; }

@media (max-width: 768px) {
  .sidebar { display: none; }
  .main-content { margin-left: 0; padding: 24px 20px 60px; }
  .main-content.full-width { padding: 24px 20px 60px; }
  .top-nav .nav-links { display: none; }
  .hero h1 { font-size: 26px; }
  .feature-grid { grid-template-columns: 1fr; }
  h1 { font-size: 24px; }
  h2 { font-size: 19px; }
}