/* Global variables and resets */
:root{
  --brand-dark:#254734; /* 墨绿 */
  --paper:#f7f1e6;     /* 米白 */
  --text:#1b1b1b;
  --muted:#6b6b6b;
  --accent:#2f6b52;
  --max-width:1280px;
  --min-width:1120px;
  --gap:24px;
  --radius:4px; /* 方形信息块，微圆角 */
  --serif: Georgia, "Times New Roman", Times, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:var(--sans);
  color:var(--text);
  background:var(--paper);
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
.container{margin:0 auto;padding:28px 20px}

/* Header: 左右分置的编辑部报头，窄报头 */
.site-head{background:var(--brand-dark);color:#fff}
.head-inner{max-width:var(--max-width);margin:0 auto;display:flex;justify-content:space-between;align-items:center;padding:10px 20px}
.brand{font-weight:700;font-size:18px;letter-spacing:0.6px}
.strap{font-size:12px;color:rgba(255,255,255,0.85);margin-top:4px}
.head-right .year{font-size:13px;opacity:0.9}

/* Page grid container: desktop will enforce a 10/2 grid; mobile will stack */
.page-frame .container{max-width:var(--max-width)}
.layout-grid{display:grid;grid-template-columns:1fr;gap:var(--gap);align-items:start}
.article{background:#fff;padding:26px;border-radius:0}
.edge-note{background:transparent;padding:0}

/* Article header: title composition: 大标题配窄元信息列 */
.title-grid{display:block}
.title{font-family:var(--serif);font-size:28px;margin:0 0 12px 0;color:var(--brand-dark);line-height:1.12}
.meta-column{font-size:13px;color:var(--muted);margin-top:8px}
.meta-item{margin-bottom:6px}
.summary{margin:14px 0 22px 0;color:var(--muted);padding-right:6px}

/* Content area */
.content{color:var(--text);font-size:16px}
.content p{margin:0 0 1em}

/* Ad blocks: independent, non-floating */
.ad{background:transparent;padding:12px 0;text-align:center}
.ad > *{display:inline-block}

/* FAQ pattern: 编号式问答但不自动生成步骤 */
.faq .section-title, .related .section-title{margin:28px 0 12px 0;font-size:16px;color:var(--accent);font-weight:600}
.faq-body{font-size:15px;color:var(--text)}
.faq-body > *{margin:8px 0}

/* Related pattern: 底部三列短卡但不用阴影 */
.related-grid{display:flex;flex-wrap:wrap;gap:12px}
.related-grid > *{flex:1 1 calc(33.333% - 8px);background:#fff;padding:10px;border-radius:2px;box-shadow:none;border:1px solid rgba(0,0,0,0.04)}
.related-grid > *:last-child{margin-right:0}

/* Edge note (right column on desktop): 方形信息块 */
.edge-note .note-block{background:#fff;padding:12px;border-radius:4px;border:1px solid rgba(0,0,0,0.06)}
.note-title{font-weight:700;color:var(--brand-dark);margin-bottom:8px}
.note-list .note-row{display:flex;justify-content:space-between;padding:6px 0;border-top:1px dashed rgba(0,0,0,0.04)}
.note-list dt{font-size:13px;color:var(--muted);margin-right:12px}
.note-list dd{margin:0;font-size:13px;color:var(--text)}

/* Visual signature: 章节标题带短编号线但不自动生成编号 */
.section-title{position:relative;padding-left:18px;display:inline-block}
.section-title::before{content:"";position:absolute;left:0;top:50%;transform:translateY(-50%);width:10px;height:2px;background:var(--accent);border-radius:1px}
.section-title::after{content:"";position:absolute;left:-2px;top:50%;transform:translateY(-50%);width:6px;height:6px;background:var(--accent);}

/* Footer */
.site-foot{padding:18px 20px;color:var(--muted);font-size:13px}
.foot-inner{max-width:var(--max-width);margin:0 auto;display:flex;justify-content:space-between}

/* Desktop specific layout: must have distinct layout (10/2) and container width between 1120-1440 */
@media (min-width:1024px){
  .page-frame .container{width:clamp(var(--min-width),90vw,var(--max-width));}
  .layout-grid{grid-template-columns:repeat(12,1fr);gap:32px}
  .article{grid-column:1 / span 10;padding:32px}
  .edge-note{grid-column:11 / span 2;padding-left:10px}

  /* Title composition: large title with narrow meta column to the right */
  .title-grid{display:grid;grid-template-columns:1fr 140px;gap:16px;align-items:start}
  .title{font-size:38px}
  .meta-column{font-size:13px;color:var(--muted);text-align:right}

  /* Related grid: three columns short cards */
  .related-grid > *{flex-basis:calc(33.333% - 8px)}
}

/* Mobile specific layout: max-width 767px; edge note folds under title and content become single column */
@media (max-width:767px){
  body{font-size:15px}
  .container{padding:16px}
  .layout-grid{grid-template-columns:1fr}
  .article{padding:18px}
  .title{font-size:20px}
  .title-grid{display:block}
  .meta-column{margin-top:8px;font-size:13px}
  .meta-column .meta-item{display:block}

  /* Edge note as block below title (并入标题下方) */
  .edge-note{order:2}
  .edge-note .note-block{margin-top:12px}

  /* Related become single-column short cards (no shadow) */
  .related-grid{flex-direction:column}
  .related-grid > *{flex-basis:100%}

  /* Ensure no horizontal scroll at 320px */
  html,body{overflow-x:hidden}
}

/* Accessibility: readable focus outlines */
a:focus{outline:2px dashed var(--accent);outline-offset:3px}