:root{color-scheme:light;--ink:#222328;--muted:#6f737b;--line:#e5e6e9;--brand:#e6434b}*{box-sizing:border-box}body{margin:0;color:var(--ink);background:#f5f6f7;font-family:"Segoe UI","Microsoft YaHei",sans-serif}main{width:min(820px,calc(100vw - 28px));margin:30px auto;padding:28px;border:1px solid var(--line);border-radius:8px;background:#fff}header{padding-bottom:20px;border-bottom:1px solid var(--line)}a{color:var(--brand);text-decoration:none}h1{margin:8px 0;font-size:26px}header p,section p,li{color:var(--muted);font-size:14px;line-height:1.85}h2{margin:26px 0 10px;font-size:17px}ul{padding-left:22px}@media(max-width:640px){main{margin:14px auto;padding:20px}h1{font-size:22px}}