:root{
  --blue:#3bb1ff;
  --red:#ff5252;
  --ink:#000;
  --paper:#f3f0e8;
  --card:#fff;
  --bd:3px solid var(--ink);
  --sh:5px 5px 0 var(--ink);
  --r:10px;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;overflow-x:hidden}
body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:"Noto Sans TC","PingFang TC","Microsoft JhengHei",system-ui,sans-serif;
  font-size:17px;
  line-height:1.72;
  -webkit-text-size-adjust:100%;
  overflow-x:hidden;
}
img{max-width:100%;height:auto;display:block}
a{color:var(--ink);text-decoration:none}
h1,h2,h3,h4{font-family:"Noto Serif TC",Georgia,"Songti TC",serif;font-weight:800;line-height:1.18;letter-spacing:-.01em;margin:0 0 .6em}
p{margin:0 0 1em}
hr{border:0;border-top:3px solid var(--ink);margin:14px 0 18px}
[id]{scroll-margin-top:104px}
.num{font-variant-numeric:tabular-nums;font-weight:700;font-size:13px;letter-spacing:.08em;font-family:"Noto Sans TC",sans-serif}
::selection{background:var(--blue)}

/* 顶部细条 */
.topbar{
  position:fixed;left:0;right:0;top:0;z-index:60;
  display:flex;align-items:center;gap:10px;
  height:42px;padding:0 18px;
  background:var(--ink);color:var(--blue);
  font-size:16px;font-weight:700;letter-spacing:.04em;
}
.topbar-txt{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.topbar-mark{color:var(--red);flex:0 0 auto}

/* 左侧竖排胶囊导航 */
.rail{
  position:fixed;left:0;top:42px;bottom:0;z-index:55;
  width:150px;padding:14px 12px;
  display:flex;flex-direction:column;gap:12px;
  overflow-y:auto;
  background:var(--paper);
  border-right:var(--bd);
}
.mark{
  display:inline-flex;align-items:center;justify-content:center;
  width:46px;height:46px;flex:0 0 auto;
  border:var(--bd);border-radius:var(--r);
  background:var(--blue);box-shadow:var(--sh);
  font-family:"Noto Serif TC",serif;font-weight:800;font-size:22px;line-height:1;
  transition:transform .12s ease,box-shadow .12s ease;
}
.mark:active{transform:translate(3px,3px);box-shadow:2px 2px 0 var(--ink)}
.rail-nav{display:flex;flex-direction:column;gap:10px}
.pill{
  display:flex;align-items:center;gap:7px;
  min-height:44px;padding:9px 10px;
  border:var(--bd);border-radius:999px;
  background:var(--card);
  font-size:16px;font-weight:700;line-height:1.3;
  box-shadow:4px 4px 0 var(--ink);
  transition:transform .12s ease,box-shadow .12s ease,background .12s ease,color .12s ease;
}
.pill .num{color:var(--red)}
.pill:hover{background:var(--blue)}
.pill:active{transform:translate(3px,3px);box-shadow:1px 1px 0 var(--ink)}
.pill.is-active{background:var(--red);color:#fff}
.pill.is-active .num{color:#fff}

/* 主结构 */
.shell{
  margin:42px 0 0 190px;
  max-width:1180px;
  padding:30px 32px 0;
  display:grid;
  grid-template-columns:214px minmax(0,1fr);
  gap:34px;
  align-items:start;
}

/* 左侧附注栏 */
.side{
  position:sticky;top:86px;
  border:var(--bd);border-radius:var(--r);
  background:var(--card);
  padding:16px 14px;
}
.side-h{font-size:19px;margin:0 0 10px}
.side-rule{margin:0 0 12px}
.toc{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:4px}
.toc a{
  display:flex;align-items:center;gap:8px;
  min-height:40px;padding:6px 8px;
  border:2px solid transparent;border-radius:8px;
  font-size:16px;font-weight:600;
}
.toc a:hover{background:var(--blue);border-color:var(--ink)}
.toc .num{color:var(--red)}

/* 顶部区 */
.hero{
  position:relative;overflow:hidden;
  display:grid;grid-template-columns:minmax(0,1fr) 150px;
  gap:24px;align-items:center;
  min-height:45vh;padding:30px;
  border:var(--bd);border-radius:var(--r);
  background:var(--card);
  background-image:radial-gradient(rgba(0,0,0,.16) 1.5px,transparent 1.5px);
  background-size:16px 16px;
}
.hero::before{
  content:"";position:absolute;left:0;top:0;
  width:14px;height:100%;
  background:var(--blue);border-right:var(--bd);
}
.hero-txt{position:relative;z-index:1;padding-left:8px}
.hero h1{font-size:clamp(2rem,4.6vw,3.3rem);margin:0 0 .5em}
.hero-lead{max-width:46ch;margin:0;font-size:17px}
.hero-art-wrap{position:relative;z-index:1;display:flex;justify-content:flex-end}
.hero-art{
  width:150px;height:150px;
  border:var(--bd);border-radius:var(--r);
  background:var(--red);object-fit:cover;
  transform:rotate(-3deg);
}
.hero-art--css{position:relative}
.hero-art--css i{position:absolute;left:15%;width:70%;height:8px;background:var(--ink)}
.hero-art--css i:first-child{top:50%;transform:rotate(45deg)}
.hero-art--css i:last-child{top:50%;transform:rotate(-45deg)}

/* 正文 */
.doc{min-width:0}
.prose{max-width:74ch}
.prose>article{padding:26px 0 30px;border-bottom:var(--bd)}
.prose>article:last-child{border-bottom:0;padding-bottom:6px}
.prose h2{font-size:clamp(1.45rem,3vw,2rem);margin-top:1.1em}
.prose h3{font-size:1.22rem;margin-top:1.2em}
.prose a{text-decoration:underline;text-decoration-thickness:2px;text-underline-offset:3px}
.prose a:hover{background:var(--blue)}
.prose ul,.prose ol{padding-left:1.35em}
.prose li{margin:.3em 0}
.prose strong{background:rgba(59,177,255,.35);padding:0 2px}
.prose blockquote{
  margin:1.2em 0;padding:12px 16px;
  border-left:6px solid var(--red);background:var(--card);
  border-radius:0 var(--r) var(--r) 0;
}
.prose img{border:var(--bd);border-radius:var(--r);margin:1em 0}
.prose pre{overflow-x:auto;padding:12px;background:var(--card);border:var(--bd);border-radius:var(--r)}
.prose code{font-size:.95em;background:var(--card);border:2px solid var(--ink);border-radius:6px;padding:1px 5px}
.prose pre code{border:0;padding:0}
.prose table{width:100%;display:block;overflow-x:auto;border-collapse:collapse;font-size:16px}
.prose th,.prose td{border:2px solid var(--ink);padding:8px 10px;text-align:left}
.prose th{background:var(--blue)}

/* 页脚 */
.foot{
  margin:56px 0 0 190px;
  border-top:var(--bd);background:var(--card);
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;
  gap:14px 26px;padding:22px 32px;
}
.foot-id{display:flex;align-items:center;gap:10px}
.mark--sm{width:40px;height:40px;font-size:19px;box-shadow:3px 3px 0 var(--ink)}
.foot-brand{font-family:"Noto Serif TC",serif;font-weight:800;font-size:17px}
.foot-nav dl{display:flex;flex-wrap:wrap;gap:0 16px;margin:0}
.foot-nav dt{margin:0}
.foot-nav a{
  display:inline-flex;align-items:center;min-height:40px;padding:4px 2px;
  font-size:16px;font-weight:700;border-bottom:3px solid transparent;
}
.foot-nav a:hover{color:var(--red);border-bottom-color:var(--red)}
.foot-meta{font-size:16px;font-weight:700}

/* 动效 */
@keyframes rise{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:none}}
.hero{animation:rise .5s .04s both}
.rail-nav .pill{animation:rise .42s both}
.rail-nav .pill:nth-child(1){animation-delay:.05s}
.rail-nav .pill:nth-child(2){animation-delay:.1s}
.rail-nav .pill:nth-child(3){animation-delay:.15s}
.rail-nav .pill:nth-child(4){animation-delay:.2s}
.rail-nav .pill:nth-child(5){animation-delay:.25s}
.rail-nav .pill:nth-child(6){animation-delay:.3s}
.rail-nav .pill:nth-child(7){animation-delay:.35s}
html.js .prose>article{opacity:0;transform:translateY(18px);transition:opacity .5s ease,transform .55s cubic-bezier(.2,.7,.3,1)}
html.js .prose>article.is-in{opacity:1;transform:none}

/* 移动端：导航压成单行横滑条，正文提到附注栏之前，保证 h1 在首屏 */
@media (max-width:900px){
  .topbar{position:static;height:auto;min-height:34px;padding:5px 14px;font-size:16px}

  .rail{
    position:static;width:auto;
    flex-direction:row;align-items:center;flex-wrap:nowrap;
    border-right:0;border-bottom:var(--bd);
    padding:7px 12px;gap:9px;overflow:hidden;
  }
  .mark{width:40px;height:40px;font-size:19px;box-shadow:3px 3px 0 var(--ink);border-radius:8px}
  .rail-nav{
    flex-direction:row;flex-wrap:nowrap;gap:8px;
    flex:1 1 auto;overflow-x:auto;overflow-y:hidden;
    padding-bottom:3px;scrollbar-width:none;
  }
  .rail-nav::-webkit-scrollbar{display:none}
  .pill{flex:0 0 auto;min-height:40px;padding:7px 12px;box-shadow:3px 3px 0 var(--ink);font-size:16px;white-space:nowrap}

  .shell{
    margin:0;max-width:none;
    padding:12px 14px 0;
    display:flex;flex-direction:column;
    gap:16px;
  }
  .doc{order:1;max-width:100%}
  .side{order:2;position:static}

  .hero{
    grid-template-columns:minmax(0,1fr);
    min-height:0;gap:12px;
    padding:16px 15px 18px 24px;
  }
  .hero h1{font-size:clamp(1.55rem,6.8vw,2.15rem);margin:0 0 .35em}
  .hero-lead{font-size:16px;max-width:none}
  .hero-art-wrap{justify-content:flex-start}
  .hero-art,.hero-art--css{width:88px;height:88px}

  .prose{max-width:none}
  .prose>article{padding:20px 0 24px}

  .foot{margin-left:0;flex-direction:column;align-items:flex-start;padding:18px 14px}
  .foot-meta{width:100%;border-top:2px solid var(--ink);padding-top:10px}
}
@media (max-width:420px){
  .rail{padding:6px 10px}
  .pill{padding:6px 10px}
  .side{padding:14px 12px}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *{animation:none!important;transition:none!important}
  html.js .prose>article{opacity:1;transform:none}
}

button[aria-expanded]{min-width:44px;min-height:44px}