:root{
  --bg:#ffffff;
  --paper:#fff;
  --ink:#2b2e31; /* 石墨灰 */
  --muted:#6b6e71;
  --accent:#caa900; /* 芥末黄 */
  --divider:#e6e6e6;
  --max-width:1280px;
  --gap:24px;
  --font-sans: system-ui, -apple-system, "Segoe UI", "Hiragino Sans GB", "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif;
}

*{box-sizing:border-box}
html,body{height:100%;margin:0;background:var(--bg);color:var(--ink);font-family:var(--font-sans);-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}

.site-header{border-bottom:2px solid var(--divider);background:linear-gradient(180deg, #f7f7f6 0%, #fafafa 100%);padding:14px 20px}
.masthead-top{display:flex;align-items:baseline;justify-content:space-between;gap:12px}
.site-name{font-weight:700;color:var(--ink);font-size:18px}
.masthead-date{color:var(--muted);font-size:12px}
.masthead-nav{margin-top:8px}
.nav-line{font-size:13px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.nav-item{padding:0 6px}
.nav-sep{color:var(--divider)}

.page-wrapper{display:flex;justify-content:center;padding:28px 16px}
.content-grid{display:grid;gap:var(--gap);width:100%;align-items:start;grid-template-columns:1fr;max-width:var(--max-width)}

/* Left rail (desktop) */
.left-rail{display:none}
.left-rail .rail-vertical{position:sticky;top:20px}
.rail-site{font-weight:700;font-size:16px;color:var(--ink)}
.rail-nav{margin-top:16px;color:var(--muted);font-size:13px}
.rail-block{border:1px solid var(--divider);background:#fff;padding:12px;margin-top:14px}
.block-title{font-size:12px;color:var(--muted);margin-bottom:6px}
.block-body{font-size:14px;color:var(--ink)}
.block-body.small{font-size:13px;color:var(--muted)}
.rail-meta{margin-top:14px;color:var(--muted);font-size:13px}

.article{background:var(--paper);padding:28px;border:0}
.article-header{max-width:900px}
.title{font-size:28px;line-height:1.15;margin:0 0 10px 0;font-weight:800;letter-spacing:-0.02em}
.title-meta{display:flex;gap:12px;color:var(--muted);font-size:13px;margin-bottom:14px}
.summary{border-left:4px solid var(--accent);padding:12px 14px;margin-bottom:18px;background:#fff;font-size:15px;color:var(--ink)}

.mobile-info{display:none;margin:12px 0;border-top:3px solid var(--accent);padding-top:8px}
.mobile-info-row{display:flex;justify-content:space-between;gap:12px;font-size:13px;color:var(--muted)}

.article-body .content{color:var(--ink);font-size:16px;line-height:1.75;max-width:920px}
.article-body .content p{margin:0 0 1em}

.ad-container{margin:20px 0;padding:12px;border:1px dashed var(--divider);background:#fafafa;color:var(--muted);font-size:13px}
.ad-top{max-width:var(--max-width);margin-left:auto;margin-right:auto}

.faq{margin-top:26px;padding-top:14px}
.faq-title{font-size:18px;margin:0 0 10px 0;padding-top:10px;border-top:4px solid var(--accent);display:inline-block}
.faq-body{margin-top:10px;color:var(--ink);font-size:15px}

.related{margin-top:22px}
.related-title{font-size:16px;color:var(--ink);margin:0 0 10px 0}
.related-list{list-style:none;padding:0;margin:0;border-top:1px solid var(--divider)}
.related-list > *{padding:12px 0;border-bottom:1px solid var(--divider);display:flex;justify-content:space-between;font-size:14px;color:var(--muted)}

.site-footer{border-top:1px solid var(--divider);padding:18px 20px;color:var(--muted);font-size:13px}

/* Desktop layout: left rail + article (3 / 9 columns) */
@media (min-width:1024px){
  .content-grid{grid-template-columns:280px 1fr;column-gap:36px;padding:28px 20px;min-width:1120px;max-width:1280px}
  .left-rail{display:block}
  .article{padding:28px 32px}
  .title{font-size:34px}
  .article-body .content{font-size:17px;line-height:1.85}
  /* visual signature: more whitespace and compact title steps */
  .article{padding-right:40px}
}

/* Mobile layout */
@media (max-width:767px){
  .content-grid{grid-template-columns:1fr;padding:16px}
  .left-rail{display:none}
  .mobile-info{display:block}
  .title{font-size:20px}
  .summary{font-size:14px;padding:10px}
  .article{padding:18px}
  .article-body .content{font-size:15px;line-height:1.9}
  .ad-container{font-size:12px}
  .related-list > *{font-size:13px}
}

/* Mid-range screens (tablet) ensure readable density */
@media (min-width:768px) and (max-width:1023px){
  .content-grid{grid-template-columns:1fr;max-width:920px;padding:20px}
  .left-rail{display:none}
  .mobile-info{display:block}
  .title{font-size:26px}
}