@import url('https://fonts.googleapis.com/css2?family=Didact+Gothic&family=Poiret+One&display=swap');

:root{
  --blue:#3bb1ff;
  --red:#ff5252;
  --ink:#000;
  --paper:#fff;
  --tint:#e9f6ff;
  --shadow:6px 6px 0 var(--ink);
  --line:3px solid var(--ink);
}

*,*::before,*::after{box-sizing:border-box}

html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:"Didact Gothic","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  font-size:17px;
  line-height:1.7;
}
img{max-width:100%;height:auto;display:block}
a{color:var(--ink)}
h1,h2,h3{
  font-family:"Poiret One","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  font-weight:700;
  line-height:1.22;
  letter-spacing:.04em;
  margin:0 0 .5em;
}

/* ---------- 页头 ---------- */
.masthead{
  display:grid;
  grid-template-columns:1fr auto 1fr;
  align-items:center;
  gap:8px;
  padding:12px 14px;
  border-bottom:4px solid var(--ink);
  background:var(--paper);
}
.mast-nav{min-width:0}
.mast-nav ol{
  display:flex;
  flex-wrap:wrap;
  list-style:none;
  margin:0;
  padding:0;
  gap:4px;
}
.mast-nav--r ol{justify-content:flex-end}
.mast-nav a{
  display:block;
  padding:11px 8px;
  min-height:44px;
  font-size:16px;
  line-height:1.4;
  text-decoration:none;
  border:2px solid transparent;
}
.mast-nav a:hover,.mast-nav a:focus-visible{
  border-color:var(--ink);
  background:var(--blue);
  box-shadow:3px 3px 0 var(--ink);
}
.brand{
  display:flex;
  align-items:center;
  gap:8px;
  padding:7px 12px;
  border:var(--line);
  background:var(--red);
  color:#fff;
  text-decoration:none;
  font-weight:700;
  letter-spacing:.08em;
  box-shadow:4px 4px 0 var(--ink);
  white-space:nowrap;
}
.brand-name{font-size:17px}
.brand-mark{font-size:19px;line-height:1}
.brand-img{width:26px;height:26px;border:2px solid var(--ink);background:#fff}

/* ---------- 粘性锚点条 ---------- */
.rail{
  position:sticky;
  top:0;
  z-index:25;
  background:var(--ink);
  border-bottom:4px solid var(--ink);
  overflow-x:auto;
  -webkit-overflow-scrolling:touch;
}
.rail-nav ol{
  display:flex;
  list-style:none;
  margin:0;
  padding:0 6px;
  gap:2px;
  white-space:nowrap;
}
.rail-nav a{
  display:block;
  padding:12px 10px;
  min-height:44px;
  font-size:16px;
  color:#fff;
  text-decoration:none;
  border-bottom:5px solid transparent;
}
.rail-nav a:hover,.rail-nav a:focus-visible,.rail-nav a[aria-current]{
  background:var(--blue);
  color:var(--ink);
  border-bottom-color:var(--red);
}

/* ---------- 顶部大图区 ---------- */
.hero{
  background:var(--blue);
  border-bottom:5px solid var(--ink);
  padding:28px 16px 0;
  text-align:center;
}
.hero-copy{max-width:760px;margin:0 auto}
.hero-title{
  font-size:clamp(30px,7vw,56px);
  margin:0 0 14px;
  text-shadow:4px 4px 0 #fff;
  word-break:break-word;
}
.hero-lede{
  display:inline-block;
  max-width:620px;
  margin:0 0 22px;
  padding:10px 16px;
  background:#fff;
  border:var(--line);
  box-shadow:5px 5px 0 var(--ink);
  font-size:17px;
}
.hero-fig{
  position:relative;
  margin:0;
  min-height:150px;
  border:var(--line);
  border-bottom:0;
  background:var(--red);
  overflow:hidden;
  clip-path:polygon(0 0,100% 0,100% 90%,0 100%);
}
.hero-img{
  width:100%;
  height:min(46vh,340px);
  object-fit:cover;
  will-change:transform;
}
.hero-cap{
  position:absolute;
  left:0;
  bottom:18px;
  padding:4px 12px;
  background:var(--ink);
  color:#fff;
  font-size:14px;
  letter-spacing:.14em;
  border-right:4px solid var(--red);
}

/* ---------- 正文与侧栏 ---------- */
.grid{
  display:grid;
  grid-template-columns:minmax(0,1fr) 300px;
  gap:32px;
  max-width:1160px;
  margin:0 auto;
  padding:34px 18px 48px;
}
.prose{min-width:0}
.prose>article{
  border:var(--line);
  box-shadow:var(--shadow);
  background:#fff;
  padding:22px 20px 26px;
  margin-bottom:32px;
  scroll-margin-top:88px;
}
.prose>article:nth-child(even){box-shadow:6px 6px 0 var(--red)}
.prose>article:nth-child(4n+3){box-shadow:6px 6px 0 var(--blue)}
.prose h2{
  font-size:clamp(22px,4vw,31px);
  padding-bottom:9px;
  margin-bottom:16px;
  border-bottom:4px solid var(--ink);
}
.prose h3{font-size:20px;margin-top:1.4em}
.prose p{margin:0 0 1em}
.prose ul,.prose ol{margin:0 0 1em;padding-left:1.35em}
.prose li{margin-bottom:.45em}
.prose blockquote{
  margin:0 0 1em;
  padding:12px 16px;
  background:var(--tint);
  border-left:9px solid var(--blue);
}
.prose figure{margin:18px 0;border:var(--line);box-shadow:5px 5px 0 var(--ink);background:var(--tint)}
.prose figure img{width:100%}
.prose figcaption{padding:8px 12px;font-size:15px;border-top:3px solid var(--ink)}
.prose table{width:100%;border-collapse:collapse;margin:0 0 1em;display:block;overflow-x:auto}
.prose th,.prose td{border:2px solid var(--ink);padding:8px 10px;text-align:left}
.prose th{background:var(--blue)}
.prose a{text-decoration:underline;text-decoration-thickness:2px}
.prose a:hover{background:var(--red);color:#fff}

.side{
  align-self:start;
  position:sticky;
  top:82px;
  padding:16px 16px 20px;
  border:var(--line);
  box-shadow:var(--shadow);
  background:var(--tint);
}
.side-t{font-size:20px;margin:0 0 8px}
.side .subtitle{
  margin:0 0 14px;
  font-weight:700;
  letter-spacing:.1em;
  color:var(--red);
  word-break:break-word;
}
.side-nav ol{display:grid;gap:8px;list-style:none;margin:0;padding:0}
.side-nav a{
  display:block;
  padding:9px 10px;
  min-height:40px;
  font-size:16px;
  text-decoration:none;
  background:#fff;
  border:2px solid var(--ink);
}
.side-nav a:hover,.side-nav a:focus-visible{background:var(--red);color:#fff}

/* ---------- 内页兜底版式 ---------- */
.leaf{
  display:grid;
  grid-template-columns:minmax(0,1fr) 300px;
  gap:32px;
  max-width:1160px;
  margin:0 auto;
  padding:32px 18px 48px;
}
.leaf-sec{min-width:0;border:var(--line);box-shadow:var(--shadow);background:#fff;padding:22px 20px 26px}
.leaf-title{font-size:clamp(26px,6vw,44px)}
.leaf-fig{margin:0 0 20px;border:var(--line);box-shadow:5px 5px 0 var(--red);background:var(--tint);min-height:120px}
.leaf-img{width:100%;height:auto}
.leaf-body h2{font-size:clamp(21px,4vw,28px);padding-bottom:8px;border-bottom:4px solid var(--ink);margin-top:1.4em}
.leaf-body p{margin:0 0 1em}

/* ---------- 页脚 ---------- */
.foot{
  background:var(--ink);
  color:#fff;
  padding:32px 18px 20px;
  border-top:8px solid var(--red);
}
.foot a{color:#fff}
.foot-top{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:26px;
  align-items:start;
  max-width:1160px;
  margin:0 auto;
}
.foot-logo{
  display:inline-block;
  padding:9px 13px;
  min-height:44px;
  border:3px solid #fff;
  box-shadow:4px 4px 0 var(--red);
  text-decoration:none;
  font-weight:700;
  letter-spacing:.08em;
}
.foot-name{margin:12px 0 0;font-size:18px;letter-spacing:.1em;color:var(--blue)}
.foot-nav ol{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:6px;
  list-style:none;
  margin:0;
  padding:0;
}
.foot-nav a{
  display:block;
  padding:10px;
  min-height:44px;
  font-size:16px;
  text-decoration:none;
  border:2px solid #fff;
}
.foot-nav a:hover,.foot-nav a:focus-visible{background:var(--blue);color:var(--ink);border-color:var(--blue)}
.foot-cta{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  max-width:1160px;
  margin:26px auto 0;
  padding:16px;
  border:3px dashed #fff;
}
.foot-k{margin:0;font-size:18px;letter-spacing:.12em;color:var(--blue)}
.cta-btn{
  display:inline-block;
  padding:12px 20px;
  min-height:44px;
  background:var(--red);
  color:#fff;
  border:3px solid #fff;
  box-shadow:4px 4px 0 #fff;
  text-decoration:none;
  font-weight:700;
  letter-spacing:.08em;
}
.cta-btn:hover,.cta-btn:focus-visible{background:var(--blue);color:var(--ink)}
.foot-bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  max-width:1160px;
  margin:24px auto 0;
  padding-top:16px;
  border-top:2px solid #fff;
}
.copy{margin:0;font-size:15px}
.top-link{
  display:inline-block;
  padding:10px 14px;
  min-height:44px;
  border:2px solid #fff;
  text-decoration:none;
}
.top-link:hover,.top-link:focus-visible{background:var(--blue);color:var(--ink);border-color:var(--blue)}

/* ---------- 滚动出现 ---------- */
html.js .reveal{opacity:0;transform:translateY(16px)}
html.js .reveal.in{
  opacity:1;
  transform:none;
  transition:opacity .5s ease,transform .5s ease;
}

/* ---------- 断点 ---------- */
@media (max-width:960px){
  .grid,.leaf{grid-template-columns:1fr}
  .side{position:static;order:2}
}
@media (max-width:780px){
  .masthead{grid-template-columns:1fr;gap:4px;padding:10px 12px}
  .brand{order:-1;justify-self:center}
  .mast-nav--r ol{justify-content:flex-start}
  .foot-top{grid-template-columns:1fr}
  .hero{padding-top:22px}
  .hero-lede{font-size:16px}
}
@media (max-width:520px){
  .mast-nav a{padding:11px 6px;font-size:16px}
  .prose>article{padding:18px 15px 22px}
  .foot{padding:26px 14px 16px}
  .foot-nav ol{grid-template-columns:1fr}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  html.js .reveal{opacity:1;transform:none}
}

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