/* Palette and base tokens */
:root{
  --brown-900:#3b2f2a; /* 深棕 */
  --cream:#f6efe6;     /* 奶油白 */
  --paper:#ffffff;     /* 正文白纸 */
  --muted:#6b605c;
  --gap:20px;
  --max-width:1280px; /* 桌面容器在1120-1440之间，取中间1280 */
  --frame-border:1px solid var(--brown-900);
  --sans:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue","Noto Sans",Arial;
}

/* Reset-ish */
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  background:var(--cream);
  color:var(--brown-900);
  font-family:var(--sans);
  -webkit-font-smoothing:antialiased;
  line-height:1.45;
  font-size:16px;
}
.visually-hidden{position:absolute;height:1px;width:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}

/* Masthead: 报刊双层报头，第二层极窄 */
.masthead{padding:18px 0 0 0}
.masthead-top{
  max-width:var(--max-width);
  margin:0 auto;
  display:flex;
  justify-content:space-between;
  align-items:flex-end;
  padding:0 var(--gap);
}
.site-title{
  text-decoration:none;
  color:var(--brown-900);
  font-weight:700;
  letter-spacing:0.02em;
  font-size:20px;
}
.masthead-meta{
  color:var(--muted);
  font-size:13px;
}
.masthead-slim{
  max-width:var(--max-width);
  margin:8px auto 18px auto;
  height:6px; /* 极窄 */
  background:linear-gradient(90deg,var(--brown-900) 0%, rgba(59,47,42,0.85) 100%);
}

/* Page frame: 外框式专题页，细边框总框架 */
.page-frame{
  max-width:var(--max-width);
  margin:0 auto 40px auto;
  background:var(--cream);
  padding:24px;
  border:var(--frame-border);
  box-shadow:none;
}

/* Grid layout: 12-col baseline; article 8 / aside 4 */
.layout-grid{
  display:grid;
  grid-template-columns:repeat(12,1fr);
  gap:24px;
  align-items:start;
}
.article{
  grid-column:1 / span 8;
  background:var(--paper);
  padding:22px;
  border-top:1px solid var(--brown-900); /* 模块通过框线区分 */
}
.sidebar{
  grid-column:9 / span 4;
  display:flex;
  flex-direction:column;
  gap:16px;
}
.side-block{
  background:var(--paper);
  padding:14px;
  border-top:1px solid var(--brown-900);
}
.block-title{font-size:13px;color:var(--muted);margin-bottom:8px}
.block-body{font-size:14px;color:var(--brown-900)}

/* Article header and title composition: 超大标题但不超过两行并紧接正文 */
.article-header{margin-bottom:10px}
.article-title{
  margin:0 0 6px 0;
  color:var(--brown-900);
  font-weight:800;
  letter-spacing:-0.01em;
  line-height:1.02;
  /* responsive large but constrained for two-line composition */
  font-size:clamp(28px, 4.2vw, 46px);
  word-break:break-word;
}
.article-meta{font-size:13px;color:var(--muted);margin-bottom:10px}
.article-meta .sep{padding:0 6px}
.summary{
  margin:0 0 14px 0;
  background:var(--paper);
  padding:10px 0 0 0;
  color:var(--muted);
  border-top:1px solid rgba(59,47,42,0.06);
}

/* Content: 以纯白纸为表面，直接完整显示 */
.article-body{color:var(--brown-900);background:var(--paper);padding-top:12px}
.content{font-size:16px;line-height:1.62;color:var(--brown-900)}
.content p{margin:0 0 12px 0}

/* Ads styled as independent containers; not floating */
.ad-slot{max-width:100%;margin:18px 0;padding:12px;border:1px dashed rgba(59,47,42,0.08);background:transparent;color:var(--muted);font-size:13px}
.ad-top{margin-bottom:22px}

/* FAQ pattern: 横线问答列表 */
.faq{margin-top:20px}
.faq-list{border-top:1px solid rgba(59,47,42,0.08)}
.faq-list > *{padding:12px 0;border-bottom:1px solid rgba(59,47,42,0.06)}
.faq-list strong{display:block;color:var(--brown-900);margin-bottom:6px}

/* Related pattern: 两列摘要列表 */
.related{margin-top:18px}
.related-heading{font-size:15px;color:var(--muted);margin:0 0 8px 0}
.related-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}
.related-grid > *{background:transparent;padding:8px 0;border-top:1px solid rgba(59,47,42,0.04)}
.related-grid a{color:var(--brown-900);text-decoration:none;font-size:14px}

/* Footer */
.page-footer{margin-top:26px;padding-top:14px;border-top:1px solid rgba(59,47,42,0.06)}
.footer-inner{font-size:13px;color:var(--muted)}

/* Density: 紧凑 */
.article, .side-block{padding:14px}

/* Visual signature: 大面积留白配紧凑字阶 */
.page-frame{padding:32px 28px}

/* 禁止圆角与阴影（遵守 forbidden_pattern） */
*{border-radius:0}

/* Desktop rules: 必须包含 @media (min-width: 1024px) */
@media (min-width:1024px){
  :root{--gap:28px}
  .page-frame{max-width:1280px;padding:36px}
  .layout-grid{gap:32px}
  .article{grid-column:1 / span 8;padding:28px}
  .sidebar{grid-column:9 / span 4}
  .article-title{font-size:44px}
  .related-grid{grid-template-columns:repeat(2,1fr)}
  /* 桌面结构差异：侧栏保持列位，标题跨栏通栏而正文采用 8/4 非对称网格 */
}

/* Mobile rules: 必须包含 @media (max-width: 767px) */
@media (max-width:767px){
  body{font-size:15px}
  .masthead-top{padding:0 14px}
  .masthead-slim{display:block;margin:6px 14px 12px}
  /* 移除总框架左右边线，保留模块顶部线 */
  .page-frame{border-left:0;border-right:0;border-top:0;border-bottom:0;padding:0;margin:0}
  .layout-grid{display:block;padding:14px}
  .article{grid-column:auto;background:var(--paper);padding:16px;border-left:0;border-right:0;border-top:1px solid var(--brown-900)}
  .sidebar{grid-column:auto;margin-top:14px}
  .side-block{padding:12px;border-top:1px solid var(--brown-900)}
  .article-title{font-size:22px;line-height:1.08}
  .article-meta{font-size:12px}
  .summary{font-size:14px;padding-top:8px}
  /* 移动端侧栏下移：自然顺序已实现 */
  .related-grid{grid-template-columns:1fr;gap:10px}
  .ad-slot{margin:14px 0}
  .page-footer{padding:12px}
  /* 确保 320px 时不横向滚动 */
  html,body{min-width:0}
}

/* Accessibility tweaks */
a{color:inherit}