:root{
  --bg:#ffffff;
  --text:#0b0b0b;
  --muted:#666666;
  --accent:#b71c1c; /* 朱红 */
  --header-bg:#0f0f0f;
  --max-desktop-width:1200px;
  --gap:20px;
  --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "Microsoft YaHei", Arial, sans-serif;
}

/* Base reset and layout */
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  color:var(--text);
  background:var(--bg);
  font-family:var(--font-stack);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  font-size:16px;
}

.masthead{background:var(--header-bg);color:#fff}
.masthead-inner{display:flex;justify-content:space-between;align-items:center;padding:12px calc((100vw - var(--max-desktop-width))/2 + 18px);}
.site-link{color:#fff;text-decoration:none;font-weight:700;letter-spacing:0.02em}
.tool-bar{font-size:13px;color:#dcdcdc}
.crumbs{opacity:0.9}
.crumb-current{color:var(--accent);font-weight:600}

.wrap{padding:22px 18px;margin:0 auto}

/* Page grid base (mobile-first) */
.page-grid{display:block}
.article{background:var(--bg);color:var(--text)}
.article-head{margin-bottom:12px}
.eyebrow{font-size:13px;color:var(--muted);font-weight:600;margin-bottom:6px}
.head-grid{display:block}
.head-left h1{margin:0;font-size:20px;line-height:1.12;font-weight:700}
.head-left h1::first-letter{color:var(--accent)} /* visual signature */
.meta{font-size:13px;color:var(--muted);margin-top:8px}
.head-right{margin-top:12px}
.summary{background:#fff;border:1px solid #eee;padding:10px;font-size:14px;color:var(--muted);margin:0}

.article-body{margin-top:18px;font-size:15px;color:var(--text)}
.article-body p{margin:0 0 14px}

.side{margin-top:22px}
.faq{border-top:3px solid var(--accent);padding-top:10px}
.faq h2{margin:0 0 8px;font-size:16px}
.faq-body{font-size:14px;color:var(--muted)}
.side-related{margin-top:18px}
.side-related-title{font-size:14px;margin:0 0 8px}
.related-list{list-style:none;padding:0;margin:0;display:block}
.related-list > *{padding:8px 0;border-bottom:1px solid #f0f0f0;color:var(--muted)}

.bottom-related{margin-top:28px}
.br-title{font-size:16px;margin:0 0 12px}
.br-grid{display:grid;grid-template-columns:1fr;gap:12px}
.br-grid > *{padding:10px;border:1px solid #f0f0f0;background:#fff;box-shadow:none;border-radius:2px}

.ad{margin:18px 0;padding:8px;border:1px dashed #e6e6e6;color:var(--muted);font-size:14px;text-align:center}
.ad-top,.ad-middle,.ad-bottom{background:#fff}

.site-footer{border-top:1px solid #efefef;padding:14px 18px;text-align:center;color:var(--muted);font-size:13px;margin-top:34px}

/* Desktop layout: distinct two-column/7-5 split and headline left/right */
@media (min-width:1024px){
  body{font-size:16px}
  .wrap{width:var(--max-desktop-width);max-width:var(--max-desktop-width);padding:32px;margin-left:auto;margin-right:auto}
  .page-grid{display:grid;grid-template-columns:7fr 5fr;gap:var(--gap);align-items:start}

  /* Article head becomes left/right halves (标题与摘要左右各半) */
  .article-head .head-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px;align-items:start}
  .head-left h1{font-size:28px}
  .head-right{align-self:start}
  .summary{border-left:4px solid rgba(183,28,28,0.06);padding:14px}

  /* Article body wide reading width, not narrow */
  .article-body{font-size:16px}

  /* Right column holds FAQ and 推荐 (contract) */
  .side{position:relative;top:0}
  .side .faq{background:#fff;padding:12px;border:1px solid #f3f3f3}
  .side-related{background:#fff;padding:12px;border:1px solid #f3f3f3;margin-top:14px}

  /* Bottom related becomes a three-column short-card grid but without shadow */
  .br-grid{grid-template-columns:repeat(3,1fr)}
  .br-grid > *{font-size:14px}
}

/* Mobile-specific rules (<=767px): independent reflow, stacked title/summary */
@media (max-width:767px){
  body{font-size:15px}
  .masthead-inner{padding:10px}
  .wrap{padding:14px}
  .page-grid{display:block}
  .head-grid{display:block}
  .head-right{margin-top:10px}
  .head-left h1{font-size:18px}
  .summary{font-size:14px}

  .article-body{font-size:15px}
  .side{margin-top:18px}
  .br-grid{grid-template-columns:repeat(1,1fr)}

  /* Ensure no horizontal scroll at 320px */
  html,body{overflow-x:hidden}
  .wrap{min-width:0}
  .article, .side, .br-grid > *{word-wrap:break-word;hyphens:auto}
}

/* Accessibility and small helpers */
h1,h2,h3{color:var(--text)}
a{color:var(--accent)}
button{font-family:var(--font-stack)}