:root{--max:980px;--border:#e6e6e6;}
*{box-sizing:border-box}
body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;margin:0;background:#f6f7fb;color:#111;overflow-x:hidden}
header{background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:9}
.wrap{max-width:var(--max);margin:0 auto;padding:14px 16px}
nav a{margin-right:14px;text-decoration:none;font-weight:800;color:#111}
main{max-width:var(--max);margin:0 auto;padding:18px 16px}
.card{background:#fff;border:1px solid var(--border);border-radius:12px;padding:16px;margin:14px 0;overflow:hidden}
h1,h2,h3,h4{line-height:1.2}
.meta{color:#555;font-weight:650}
.breadcrumb{font-size:14px;color:#555;margin:10px 0 12px}
.breadcrumb a{text-decoration:none;font-weight:800;color:#111}
.breadcrumb .sep{margin:0 6px;color:#888}
.toc{background:#fafafa;border:1px solid var(--border);border-radius:12px;padding:14px;margin:14px 0 18px}
.toc a{text-decoration:none;font-weight:800}
.btn{display:inline-block;padding:10px 14px;border-radius:10px;border:1px solid #ddd;background:#fff;font-weight:800;text-decoration:none;color:#111}
img.resp{max-width:100% !important;width:100% !important;height:auto !important;display:block;border-radius:12px;border:1px solid var(--border)}
.figure{margin:14px 0}
.figure figcaption{margin-top:8px}
footer{background:#fff;border-top:1px solid var(--border);margin-top:24px}
.small{font-size:13px;color:#555}
@media (max-width:520px){nav a{display:inline-block;margin:6px 10px 0 0}}