:root{
  --paper:#fbfaf8; /* 轻纸张底色 */
  --charcoal:#1f2224; /* 炭黑 */
  --warm-gray:#9b948e; /* 暖灰 */
  --accent:#1f2224; /* 视觉竖线颜色，沿用炭黑 */
  --muted:#6f6b66;
  --max-width:1280px; /* 桌面容器宽度，1120-1440 之间选用 */
  --gap:24px;
  --density-line:1.45;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans CJK SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

/* 全局轻纸张底和紧凑排版 */
html,body{height:100%;background:var(--paper);color:var(--charcoal);margin:0;font-size:16px;line-height:var(--density-line);}
a{color:var(--charcoal);text-decoration:none}
.container, .layout-container{box-sizing:border-box}

/* Header: 居中刊头与横线导航 */
.site-header{padding:18px 16px 8px;border-bottom:0}
.top-nav{display:flex;align-items:center;justify-content:space-between;max-width:var(--max-width);margin:0 auto;padding:0 16px}
.top-nav .nav-left,.top-nav .nav-right{color:var(--muted);font-size:13px;display:flex;gap:12px}
.top-nav .nav-center{position:relative;text-align:center;flex:1}
.site-name{font-weight:700;font-size:18px}
.nav-divider{border:none;height:1px;background:linear-gradient(90deg,transparent,rgba(0,0,0,0.06),transparent);margin:12px 0}

/* 布局：默认单列（mobile-first），桌面端切换为 reverse-rail */
.layout-container{display:flex;flex-direction:column;gap:var(--gap);padding:16px;margin:0 auto}
.side-left, .content-rail{box-sizing:border-box}

/* 侧边与正文内容基础样式（移动端） */
.side-left{order:1}
.side-left .aside-site{font-weight:700;color:var(--charcoal);margin-bottom:8px}
.side-left .breadcrumb{font-size:13px;color:var(--muted);margin-bottom:8px}
.side-left .aside-meta{font-size:13px;color:var(--muted);display:flex;flex-direction:column;gap:6px}
.related-block{margin-top:18px}
.related-block h2{font-size:14px;margin:0 0 8px;color:var(--charcoal)}
.related-list{padding-left:18px;margin:0;color:var(--muted)}
.related-list li{margin:6px 0}

.content-rail{order:2}
.ad-slot{background:transparent;padding:6px 0;color:var(--muted);font-size:13px}
.article-header{padding:8px 0}
.title-composition{display:flex;flex-direction:column;gap:10px}
.title-composition h1{font-size:22px;margin:0 0 6px;line-height:1.08}
.title-meta{font-size:13px;color:var(--muted)}
.title-meta .summary{margin:6px 0 0}
.article-body{margin-top:10px}
.body-label{font-size:13px;color:var(--muted);margin-bottom:8px}
.body-content{color:var(--charcoal)}
.faq-section{margin-top:22px}
.faq-section h2{font-size:14px;margin:0 0 10px}
.faq-grid{display:block;color:var(--muted)}

.site-footer{padding:18px 16px;text-align:center;font-size:13px;color:var(--muted)}

/* 视觉签名：贯穿页面的1px主题竖线（移动端隐藏） */
.signature-line{display:none}

/* 桌面规则：1024px 及以上采用 reverse-rail 双栏 4:8 网格 */
@media (min-width: 1024px){
  .layout-container{display:grid;grid-template-columns:4fr 8fr;gap:32px;max-width:var(--max-width);min-width:1120px;padding:28px;align-items:start}

  .side-left{order:0;padding-right:28px;border-right:1px solid var(--accent);}
  /* 1px 主题竖线作为侧栏右边框，贯穿视觉 */
  .signature-line{display:block}

  .side-left .aside-top{margin-bottom:18px}
  .side-left .aside-meta{margin:12px 0 20px}
  .related-block{margin-top:14px}
  .related-list{list-style:none;padding:0;counter-reset:rel;}
  .related-list > li{counter-increment:rel;padding:8px 0;border-bottom:1px dashed rgba(0,0,0,0.04)}
  .related-list > li::before{content:counter(rel)".";display:inline-block;width:30px;color:var(--warm-gray);}

  /* 内容区：标题组合为大标题 + 窄元信息列 */
  .article-header .title-composition{display:grid;grid-template-columns:1fr 220px;gap:18px;align-items:start}
  .title-composition h1{font-size:34px}
  .title-meta{font-size:13px;color:var(--muted)}
  .title-meta .summary{margin-top:6px}

  .article-body{font-size:16px}
  .body-content{line-height:1.6}

  /* FAQ 桌面表格式：左问题右答案 */
  .faq-grid{display:grid;grid-template-columns:220px 1fr;gap:12px}
  .faq-grid > *{padding:8px 0;border-bottom:1px solid rgba(0,0,0,0.03)}

  /* 广告位置样式，保持独立容器，不悬浮、不覆盖 */
  .ad-slot{border-top:1px dashed rgba(0,0,0,0.04);padding:12px 0;margin:14px 0;color:var(--muted)}
}

/* 手机规则：最大宽度 767px，独立重排，左侧信息拆分为标题前后紧凑区块 */
@media (max-width: 767px){
  :root{font-size:15px}
  .layout-container{padding:12px}
  .side-left{display:none} /* 桌面左侧整体隐藏，改用 mobile-meta-* 在文章中展示 */

  .mobile-meta-top{display:block;font-size:13px;color:var(--muted);margin:8px 0}
  .mobile-meta-bottom{display:block;font-size:13px;color:var(--muted);margin-top:12px}

  .title-composition h1{font-size:20px}
  .title-composition{gap:8px}
  .title-meta{font-size:13px}

  .article-body{margin-top:8px}
  .body-content{font-size:15px}

  .related-block{margin-top:16px}
  .related-list{padding-left:16px}

  .faq-grid{display:block}
  .faq-grid > *{padding:10px 0;border-top:1px solid rgba(0,0,0,0.04)}

  .ad-slot{padding:10px 0;color:var(--muted)}

  /* 防止 320px 横向滚动 */
  body, .layout-container, .content-rail{min-width:0;word-break:break-word}
}

/* 中性微交互：保持轻量 */
a:hover{text-decoration:underline}