/* 设计变量与重置 */
:root{
  --navy:#0b2a4a; /* 藏蓝 */
  --paper:#fbf9f2; /* 轻纸张 */
  --muted:#6b7280;
  --content-width-min:1120px;
  --content-width-max:1440px;
  --gutter:24px;
  --track-border:rgba(11,42,74,0.08);
  --line:rgba(11,42,74,0.12);
  --title-size:clamp(24px,3.4vw,40px);
  --body-size:16px;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', 'Microsoft Yahei', sans-serif;
  color-scheme: light;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  background:var(--paper);
  color:var(--navy);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  line-height:1.65;
  font-size:var(--body-size);
}
a{color:var(--navy); text-decoration:none}
a:focus{outline:2px solid rgba(11,42,74,0.12)}
.site-header{padding:18px 16px; border-bottom:1px solid var(--track-border); background:transparent}
.brand-row{max-width:1200px;margin:0 auto;display:flex;align-items:center;gap:12px}
.brand{font-weight:700;color:var(--navy);font-size:16px}
.nav-trail{color:var(--muted);font-size:13px}
.ledger-container{max-width:var(--content-width-max);margin:20px auto;padding:0 16px}
.ledger-article{background:transparent}
.article-header{margin-bottom:12px}
.article-title{
  margin:0 0 8px 0;
  font-size:var(--title-size);
  line-height:1.05;
  font-weight:700;
  letter-spacing:-0.02em;
  word-break:break-word;
  max-height:calc(1.05 * 2 * var(--title-size)); /* 不超过两行 */
  overflow:hidden;
}
.meta-row{display:flex;justify-content:space-between;align-items:center;gap:12px;font-size:13px;color:var(--muted)}
.meta-left{display:flex;gap:12px;align-items:center}
.meta-track{display:none}
.summary{margin:12px 0;color:var(--muted);font-size:15px}
.grid-layout{display:block}
/* 广告样式：独立容器，不悬浮、不覆盖 */
.ad-slot{margin:18px 0;padding:10px;border:1px dashed var(--line);background:transparent;color:var(--muted);font-size:13px}
.ad-slot[aria-hidden="true"]{pointer-events:none}

.section-title{
  display:flex;align-items:center;gap:10px;font-size:15px;margin:12px 0 8px 0;padding:0;color:var(--navy);font-weight:600
}
/* 视觉识别：章节标题带短编号线（不自动生成数字） */
.section-title::before{
  content:"";
  display:inline-block;
  width:28px;height:2px;background:var(--navy);transform:translateY(-1px);
}

.content{min-height:120px}
.content p{margin:0 0 12px 0}
.content h2{margin:18px 0 8px 0}
.content h3{margin:14px 0 8px 0}

.related{margin-top:20px}
.related-list{counter-reset:related-counter;display:block}
/* 兼容多种运行时代入形式：若为一组链接或列表，下面规则为直接子节点添加编号 */
.related-list > *{display:block;padding:6px 0;border-top:1px solid var(--line);position:relative;padding-left:28px}
.related-list > *::before{counter-increment:related-counter;content:counter(related-counter)".";position:absolute;left:0;color:var(--muted);font-size:13px}

.faq-list details{border-top:1px solid rgba(11,42,74,0.06);padding:10px 0}
.faq-list summary{cursor:pointer;font-weight:600}
.faq-list summary::-webkit-details-marker{display:none}

.site-footer{padding:18px 16px;border-top:1px solid var(--track-border);color:var(--muted);font-size:13px;text-align:center}

/* 桌面布局：ledger-grid（硬性合同） */
@media (min-width:1024px){
  .ledger-container{min-width:var(--content-width-min);max-width:var(--content-width-max)}
  .meta-track{display:block}

  .grid-layout{display:grid;grid-template-columns:repeat(12,1fr);gap:24px;align-items:start}
  .article-header{grid-column:1 / -1}
  .article-title{grid-column:1 / -1}

  /* 正文占7列 */
  .content{grid-column:1 / 8;padding-right:12px;border-right:1px solid var(--track-border)}

  /* FAQ 占3列 */
  .faq{grid-column:8 / 11;padding-left:16px}
  .faq .section-title{margin-top:0}

  /* 元信息轨道占2列，直角线框语言 */
  .side-track{grid-column:11 / 13;border-left:1px solid var(--track-border);padding-left:16px}
  .track-box{position:sticky;top:20px;display:flex;flex-direction:column;gap:10px}
  .track-row{font-size:13px;color:var(--muted)}

  /* 让标题横跨12列并紧接正文（布局上已保证） */
  .article-header .summary{max-width:80%}
}

/* 手机端：网格解除，线框只保留为段落顶部细线；单独排版 */
@media (max-width:767px){
  .ledger-container{padding:12px}
  .brand-row{padding:0}
  .article-title{font-size:20px;margin-top:6px}
  .meta-row{flex-direction:column;align-items:flex-start;gap:6px}
  .meta-track{display:none}
  .grid-layout{display:block}
  .content{padding:0;border-right:none}
  .faq{margin-top:12px}
  .side-track{display:none}
  .section-title::before{width:20px}

  /* 线框弱化为段落顶部细线：为直接子段落添加边线 */
  .content > *{border-top:1px solid var(--line);padding-top:12px}
  .content > *:first-child{border-top:none;padding-top:0}

  .related-list > *{padding-left:22px}
}

/* 访问性与打印优化 */
@media print{
  .ad-slot{display:none}
  .brand-row,.site-footer{display:none}
}