/* Palette & core variables (深紫灰与象牙白) */
:root{
  --bg: #f7f5f0; /* 象牙白 */
  --panel-bg: #ffffff;
  --text: #22223b; /* 深灰/紫色基调 */
  --muted: #6b6b78;
  --accent: #3b2f5a; /* 深紫灰 */
  --rule: #d9d7d3; /* 细灰线 */
  --max-width: 1280px; /* 在 1120-1440 之间 */
  --gap: 28px;
  --touch-min: 44px;
}

/* Basic reset and typography */
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft Yahei", "Noto Sans CJK SC", Arial, sans-serif;
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}

/* Header: 左右分置的编辑部报头，双层报头但第二层极窄 */
.site-header{background:var(--panel-bg);border-bottom:1px solid var(--rule);padding:18px 20px 8px}
.header-row{display:flex;align-items:center;justify-content:space-between}
.header-row--top .branding{font-weight:700;color:var(--accent);letter-spacing:0.2px}
.home-link{font-size:18px}
.header-row--narrow{margin-top:8px;padding-top:8px;border-top:1px solid var(--rule);font-size:13px;min-height:28px}
.utility-nav{display:flex;gap:12px;align-items:center}
.utility-nav .nav-item{padding:4px 8px;color:var(--muted)}

/* Top nav strip: horizontal, mobile scrollable */
.top-nav-strip{background:transparent;border-bottom:1px solid transparent;padding:10px 0}
.top-nav-scroll{display:flex;gap:16px;overflow-x:auto;padding:6px 4px}
.top-nav-scroll::-webkit-scrollbar{display:none}
.tn-item{white-space:nowrap;padding:6px 10px;border:1px solid var(--rule);min-height:var(--touch-min);display:inline-flex;align-items:center}

/* Layout grid: desktop two-column (宽主栏+窄侧栏)，mobile single column */
.layout-grid{display:block;padding:28px 20px 40px;max-width:var(--max-width);margin:0 auto}

.main-article{background:transparent}
.article-head{margin-bottom:18px;padding-bottom:12px;border-bottom:1px solid var(--rule)}
.title{font-family: Georgia, 'Times New Roman', Times, serif; font-size:34px;line-height:1.12;text-align:center;margin:28px 0 10px;color:var(--accent)}
.meta{display:flex;gap:8px;justify-content:center;color:var(--muted);font-size:13px}
.summary{max-width:980px;margin:18px 0 0;padding-left:0;color:var(--muted);text-align:left}

.article-body{margin-top:18px;color:var(--text);font-size:16px}
.article-body p{margin:0 0 16px}

/* Ads: independent containers, non-floating */
.ad-slot{background:transparent;padding:12px 0;text-align:center}
.ad-slot:empty{display:none}

/* FAQ with theme-color top border */
.faq{margin-top:28px;padding-top:18px;border-top:4px solid var(--accent)}
.faq h2{font-size:18px;margin:0 0 12px}
.faq-list{color:var(--muted)}

/* Related: 四列紧凑标题网格在桌面 */
.related{margin-top:20px}
.related h3{font-size:15px;margin:0 0 12px}
.related-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}
.related-grid > *{padding:8px 6px;border-top:1px solid var(--rule);font-size:14px;color:var(--accent)}

/* Sidebar panels (窄侧栏) */
.page-side{margin-top:24px}
.side-panel{background:var(--panel-bg);border-top:1px solid var(--rule);padding:12px 10px;margin-bottom:12px}
.panel-title{font-size:13px;color:var(--muted);margin-bottom:8px}
.panel-body{font-size:14px;color:var(--text)}

/* Footer */
.site-footer{border-top:1px solid var(--rule);padding:18px 20px;text-align:center;color:var(--muted);font-size:13px}

/* Desktop rules (>=1024px): 双栏、非对称网格、通栏元素 */
@media (min-width:1024px){
  .layout-grid{display:grid;grid-template-columns:1fr 300px;gap:var(--gap);padding:36px 20px 60px;align-items:start;min-width:1120px}
  .main-article{grid-column:1 / 2}
  .page-side{grid-column:2 / 3;position:relative;top:0}

  /* Ensure main column is wide and not constrained to small mobile widths */
  .article-body{font-size:18px}
  .title{font-size:44px}

  /* Related grid becomes four columns compact */
  .related-grid{grid-template-columns:repeat(4,1fr);gap:12px}
  .related-grid > *{padding:6px 8px;border-top:none;border-left:1px solid var(--rule)}

  /* Visual signature: large whitespace with compact letter scale */
  .article-head{padding-bottom:18px;margin-bottom:26px}
}

/* Mobile rules (<=767px): 独立重排，侧栏下移，横向导航可滚动，触控区 >=44px */
@media (max-width:767px){
  :root{--gap:18px}
  .layout-grid{display:block;padding:18px 14px}
  .title{font-size:22px;margin:20px 0}
  .meta{justify-content:flex-start;padding-left:2px}
  .summary{font-size:14px;margin-top:10px}
  .article-body{font-size:15px}

  /* Make nav items touch-friendly */
  .tn-item{min-height:var(--touch-min);padding:10px 14px}
  .utility-nav .nav-item{min-height:var(--touch-min);display:inline-flex;align-items:center;padding:6px 10px}

  /* Sidebar becomes stacked under article */
  .page-side{margin-top:26px}
  .related-grid{grid-template-columns:repeat(2,1fr)}

  /* Avoid horizontal scroll at 320px and prevent text clipping */
  body{word-break:break-word}
  .top-nav-scroll{padding-bottom:2px}
}

/* Accessibility and small adjustments */
.title, .summary, .article-body{max-width:100%}
.panel-body, .faq-list{word-wrap:break-word}