:root{
  --bg:#f6f6f6;
  --paper:#ffffff;
  --ink:#2b2b2b; /* 石墨灰基色 */
  --muted:#6b6b6b;
  --accent:#b59a00; /* 芥末黄 */
  --max-width:1280px;
  --gutter:24px;
  --serif: Georgia, "Times New Roman", serif;
  --ui: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

/* Reset & base */
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  color:var(--ink);
  background:var(--bg);
  font-family:var(--serif);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  line-height:1.65;
  -webkit-text-size-adjust:100%;
}

a{color:inherit; text-decoration:none}

.site-header{
  background:transparent;
  padding:14px var(--gutter);
}
.site-header .brand{
  display:flex;align-items:center;gap:18px;
}
.site-header .home{
  font-family:var(--ui);
  font-weight:700;
  color:var(--ink);
  font-size:18px;
}
.nav-index{display:flex;gap:12px;color:var(--muted);font-family:var(--ui);font-size:13px}
.nav-index span{padding:6px 0}

/* Layout container */
.page-layout{
  max-width:var(--max-width);
  margin:18px auto;
  padding:0 var(--gutter);
  display:grid;
  gap:28px;
}

/* Rail (left) and Article (right) baseline styles */
.rail{order:1}
.article{order:2}

/* Article */
.article{background:transparent}
.article-header{padding:8px 0 12px}
.title{
  margin:6px 0 10px;
  font-family:var(--serif);
  color:var(--ink);
  font-weight:700;
  line-height:1.15;
  /* 超大标题但尽量控制在两行：使用 clamp 控制字号 */
  font-size:clamp(22px, 3.6vw, 36px);
}

.meta-row{display:flex;gap:18px;flex-wrap:wrap;color:var(--muted);font-family:var(--ui);font-size:13px}
.summary{color:var(--muted);margin:12px 0 18px;font-size:16px}

.content-body{background:var(--paper);padding:22px;border-radius:0;box-shadow:none}
.content-body p{margin:0 0 1em;color:var(--ink);font-size:17px}

/* Visual signature for chapter headings inside content */
.content-body h2, .content-body h3{
  position:relative;
  margin:1.4em 0 0.6em;
  padding-left:34px;
  font-family:var(--serif);
  color:var(--ink);
}
.content-body h2::before, .content-body h3::before{
  content:"";
  position:absolute;
  left:10px;top:50%;transform:translateY(-50%);
  width:18px;height:3px;background:var(--accent);border-radius:2px;
}
.content-body h2::after, .content-body h3::after{
  /* short decorative square — visual signature without numbering */
  content:"";
  position:absolute;left:6px;top:50%;transform:translateY(-50%);
  width:6px;height:6px;background:var(--accent);border-radius:2px;
}

/* FAQ pattern: 顶部边线主题色 */
.faq{margin-top:26px;padding:14px 18px;border-top:4px solid var(--accent);background:transparent}
.faq-title{margin:0 0 8px;font-family:var(--ui);color:var(--ink);font-size:16px}
.faq-body{color:var(--muted)}

/* Related pattern: 四列紧凑标题网格 (desktop) */
.related-grid{display:grid;gap:10px;grid-auto-rows:minmax(36px,auto)}
.related-grid > *{font-family:var(--ui);font-size:14px;color:var(--muted)}

/* Ads (non-floating, independent containers) */
.ad-slot{background:transparent;padding:10px 0;color:var(--muted);font-family:var(--ui);font-size:13px}
.ad-slot:not(:empty){border-top:1px dashed rgba(0,0,0,0.04)}

.article-footer{margin-top:28px;padding-top:12px;color:var(--muted);font-family:var(--ui);font-size:14px}
.related-footer .related-grid-footer{margin-top:8px}

/* Side column details */
.rail{padding:6px}
.side-compact{display:none}
.side-meta{margin-top:12px;color:var(--muted);font-family:var(--ui);font-size:13px}
.side-meta .meta-item{margin-bottom:8px}
.side-related h3{font-family:var(--ui);font-size:14px;margin:12px 0}
.side-related .related-grid > *{padding:4px 0}

/* Footer */
.site-footer{padding:18px var(--gutter);text-align:left;color:var(--muted);font-family:var(--ui);font-size:13px}

/* Desktop: min-width 1024px rules */
@media (min-width:1024px){
  .page-layout{
    grid-template-columns: 320px 1fr; /* left ~320px, right fills */
    align-items:start;
    gap:36px;
    padding-top:18px;padding-bottom:36px;
  }

  /* Ensure container width within 1120-1440: set max-width 1280 (in root) and center */
  body > .page-layout{max-width:var(--max-width)}

  /* Reverse rail: left side narrow (4 cols), right main wide (8 cols) */
  .rail{order:1}
  .article{order:2}

  .article{max-width:900px}

  /* Related grid: 4 columns compact */
  .related-grid{grid-template-columns:repeat(4,1fr)}
  .related-grid > *{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

  /* Article content uses wider measure */
  .content-body{font-size:17px;line-height:1.8}

  /* Desktop-only structural difference: show a subtle left editorial rail visual */
  .rail{border-right:1px solid rgba(0,0,0,0.03);padding-right:22px}
}

/* Mobile: max-width 767px rules - independent mobile layout */
@media (max-width:767px){
  html,body{font-size:16px}
  .page-layout{display:block;padding:12px}
  .rail{order:2;border:0;padding:0;margin-top:18px}
  .article{order:1}

  /* Split left-side info into compact blocks: place small meta before & after title via reflow */
  .meta-top-mobile{display:block;margin-bottom:10px;color:var(--muted);font-family:var(--ui);font-size:13px}
  .meta-top-mobile::before{content:attr(data-published);}

  /* We cannot auto-insert variables into pseudo; instead we show the mobile compact blocks by moving existing meta elements */
  .meta-row{display:flex;flex-direction:column;gap:8px}

  .title{font-size:clamp(20px,6.4vw,30px)}
  .summary{font-size:15px}

  /* Content full width, comfortable measure */
  .content-body{padding:16px;background:var(--paper)}

  /* Related grid becomes 2 columns on small screens to avoid overcrowd */
  .related-grid{grid-template-columns:repeat(2,1fr);gap:8px}
  .related-grid > *{white-space:normal}

  /* Ensure no horizontal scrolling at 320px */
  body{word-wrap:break-word;overflow-x:hidden}
  .content-body img, .content-body table{max-width:100%;height:auto}
}

/* Accessibility & density adjustments */
@media (prefers-reduced-motion:reduce){
  *{transition:none!important}
}