:root{
  --bg:#f7f5f0; /* 纸白 */
  --paper:#ffffff;
  --text:#111111;
  --muted:#666666;
  --accent:#0b3850; /* 藏蓝强调色 */
  --surface-radius:2px;
  --container-min:1120px;
  --container-max:1200px;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:system-ui,-apple-system,Segoe UI,Roboto,"Helvetica Neue","Noto Sans CJK SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  background:var(--bg);
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  line-height:1.6; /* 基线 */
}
.site-header{
  background:transparent;
  padding:18px 20px 8px;
  border-bottom:1px solid rgba(11,56,80,0.08);
}
.header-row{
  display:flex;
  align-items:center;
  justify-content:space-between;
  max-width:var(--container-max);
  margin:0 auto;
}
.nav-side{color:var(--muted);font-size:13px}
.site-name a{color:var(--text);text-decoration:none;font-weight:700;letter-spacing:1px}
.paper-head{max-width:var(--container-max);margin:10px auto 0;display:flex;flex-direction:column;align-items:center}
.paper-title{font-size:18px;color:var(--muted);letter-spacing:2px}
.paper-sub{font-size:12px;color:var(--muted);margin-top:2px}
.ad{max-width:var(--container-max);margin:12px auto;padding:6px 0;text-align:center}
.container{max-width:var(--container-max);margin:18px auto;padding:0 18px}
.grid{
  display:grid;
  grid-template-columns:1fr; /* mobile default */
  gap:28px;
}
.article{background:var(--paper);border:1px solid rgba(11,56,80,0.06);border-radius:var(--surface-radius);padding:20px}
.article-head h1{
  margin:0 0 8px 0;
  font-size:28px; /* mobile title smaller */
  line-height:1.05;
  color:var(--text);
  letter-spacing:-0.01em;
}
.meta-row{display:flex;flex-wrap:wrap;gap:10px;font-size:13px;color:var(--muted);align-items:center}
.meta-row time{font-variant-numeric:tabular-nums}
.summary{margin-top:12px;color:var(--muted);font-size:15px}
.article-body{
  margin-top:16px;
  color:var(--text);
  font-size:15px;
  line-height:1.9; /* 舒展的行高 */
  /* 双层基线网格视觉签名：细微的水平线条不影响可读性 */
  background-image:
    linear-gradient(rgba(11,56,80,0.02) 1px, transparent 1px),
    linear-gradient(rgba(11,56,80,0.01) 1px, transparent 1px);
  background-size:100% 36px, 100% 18px; /* 双层基线：主线36px，次线18px */
  background-position:0 0, 0 0;
  padding:14px;
  border-radius:var(--surface-radius);
  border:1px solid rgba(11,56,80,0.03);
}
.article-body p{margin:0 0 12px}
.faq{margin-top:22px;padding-top:12px;border-top:3px solid var(--accent)}
.faq h2{margin:6px 0 10px;font-size:16px}
.faq-body{color:var(--muted)}
.side{display:flex;flex-direction:column;gap:18px}
.side-panel{background:var(--paper);padding:12px;border:1px solid rgba(11,56,80,0.05);border-radius:var(--surface-radius)}
.side-title{margin:0 0 8px 0;font-size:14px;color:var(--accent)}
.meta-list{margin:0;padding:0;font-size:13px;color:var(--muted)}
.meta-list dt{font-weight:700;color:var(--text);margin-top:8px}
.meta-list dd{margin:0 0 6px 0}
.related-panel .related-list{display:flex;flex-direction:column;gap:8px}
.related-grid{margin-top:18px;display:grid;grid-template-columns:1fr;gap:12px}
.section-title{font-size:15px;color:var(--text);margin:0 0 8px}
.site-footer{padding:18px 0;text-align:center;color:var(--muted);font-size:13px}
.surface{border-radius:var(--surface-radius)}
.truncate{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
/* Desktop rules: 核心要求的 8/4 分栏、超大但不遮挡首屏标题、细线网格主视觉 */
@media (min-width:1024px){
  body{background:var(--bg)}
  .container{max-width:1200px;padding:0 24px}
  .grid{grid-template-columns:8fr 4fr;align-items:start;gap:32px}
  .article{padding:28px}
  .article-head h1{font-size:56px;line-height:1.02;margin-bottom:6px}
  .paper-head{align-items:flex-start;padding-left:24px}
  .paper-title{font-size:14px}
  .paper-sub{font-size:12px}
  /* 细线网格主视觉：在 article 外层轻微网格线条辅助视觉，但不遮挡内容 */
  .container::before{
    content:"";
    position:relative;display:block;width:100%;height:12px;background:
      linear-gradient(transparent 0 calc(100% - 1px), rgba(11,56,80,0.03) calc(100% - 1px) 100%);
    transform:translateY(0);
    pointer-events:none;
  }
  .article-body{font-size:16px;line-height:1.95;background-size:100% 38px,100% 19px}
  .related-grid{grid-template-columns:repeat(3,1fr);gap:16px}
  .related-grid > *{background:var(--paper);padding:10px;border:1px solid rgba(11,56,80,0.05);border-radius:var(--surface-radius)}
  .side{position:relative}
  .ad.ad-middle{order:2;margin-top:18px}
}
/* Mobile rules: 单列、标题比例缩小、侧栏下移 */
@media (max-width:767px){
  .container{padding:10px}
  .paper-head{align-items:center}
  .article{padding:16px}
  .article-head h1{font-size:20px}
  .meta-row{font-size:12px}
  .article-body{font-size:15px;line-height:1.8;background-size:100% 34px,100% 17px}
  .related-grid{grid-template-columns:1fr}
  .side{order:3}
  .related-panel{display:none} /* 手机端将侧栏相关阅读改为底部自然区块，避免固定侧栏 */
}
/* 可访问性与可读性微调 */
a{color:var(--accent);text-decoration:none}
a:focus{outline:2px solid rgba(11,56,80,0.12);outline-offset:2px}
/* 小屏避免横向滚动 */
img,table,pre{max-width:100%;height:auto}