/* 基础主题变量与暗色模式支持 */
:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #222222;
  --muted: #666666;
  --primary: #0b7dda;
  --accent: #0aa06e;
  --border: #e6e6e6;
  --radius: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
  --shadow-md: 0 3px 10px rgba(0,0,0,0.12);
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #111111; --fg: #eaeaea; --muted: #9aa0a6; --border: #333333; }
}

/* 基础排版与容器 */
html, body { margin: 0; padding: 0; }
body { background: var(--bg); color: var(--fg); font-family: system-ui, -apple-system, Segoe UI, Roboto, "PingFang SC", "Microsoft YaHei", Arial, sans-serif; line-height: 1.7; }
.container { max-width: 960px; margin: 0 auto; padding: 24px; }

/* 顶部与导航 */
header { border-bottom: 1px solid var(--border); backdrop-filter: saturate(120%) blur(4px); }
nav { display: flex; gap: 12px; padding: 12px 0; flex-wrap: wrap; }
nav a { color: var(--primary); text-decoration: none; font-weight: 600; }
nav a:hover { text-decoration: underline; }
a:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; border-radius: 4px; }

/* 面包屑 */
.breadcrumb { font-size: 14px; color: var(--muted); margin: 12px 0; }
.breadcrumb a { color: var(--muted); text-decoration: none; }
.breadcrumb a:hover { text-decoration: underline; }

/* 标题与文本 */
h1 { font-size: 28px; margin: 16px 0 8px; }
h2 { font-size: 24px; margin: 24px 0 8px; }
h3 { font-size: 18px; margin: 20px 0 8px; }
p { margin: 8px 0; }
ul { margin: 8px 0 16px 20px; }
.muted { color: var(--muted); }
ol { margin: 8px 0 16px 24px; }

/* 卡片与按钮 */
.card { border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; margin: 16px 0; background: rgba(255,255,255,0.02); box-shadow: var(--shadow-md); }
.cta { display: inline-block; padding: 10px 16px; border-radius: 6px; background: var(--accent); color: #fff; text-decoration: none; font-weight: 700; }
.cta { box-shadow: var(--shadow-sm); transition: transform .15s ease, box-shadow .15s ease, opacity .2s ease; }
.cta:hover { opacity: 0.95; transform: translateY(-1px); box-shadow: 0 6px 16px rgba(0,0,0,0.2); }

/* 页脚 */
footer { border-top: 1px solid var(--border); margin-top: 24px; padding-top: 16px; color: var(--muted); font-size: 14px; }

/* Hero 区块 */
.hero { border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; margin: 18px 0 24px; background:
  linear-gradient(135deg, rgba(11,125,218,0.08), rgba(10,160,110,0.08)); box-shadow: var(--shadow-md); }
.hero h2 { margin-top: 0; font-size: 26px; }
.hero p { color: var(--muted); max-width: 70ch; }
.hero .cta { margin-top: 10px; }

/* 标签（关键词 chips） */
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { display: inline-block; padding: 6px 10px; border-radius: 999px; border: 1px solid var(--border); background: rgba(11,125,218,0.08); color: var(--fg); font-size: 13px; }
.chip--accent { background: rgba(10,160,110,0.08); }

/* 响应式优化 */
@media (max-width: 640px) {
  .container { padding: 16px; }
  h1 { font-size: 24px; }
  h2, .hero h2 { font-size: 22px; }
  .hero { padding: 20px; }
}