@import url('https://fonts.googleapis.com/css2?family=Atkinson+Hyperlegible:wght@400;700&family=Crimson+Pro:wght@400;500;600;700&display=swap');

:root{
  --blue:#3bb1ff;
  --red:#ff5252;
  --ink:#000;
  --paper:#f7f3e8;
  --line:3px solid #000;
  --shadow:6px 6px 0 #000;
  --ui:"Atkinson Hyperlegible","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --serif:"Crimson Pro",Georgia,"Songti SC","Noto Serif SC",serif;
}

*{box-sizing:border-box}

html{
  scroll-behavior:smooth;
  -webkit-text-size-adjust:100%;
}

body{
  margin:0;
  font-family:var(--serif);
  font-size:17px;
  line-height:1.75;
  color:var(--ink);
  background-color:var(--paper);
  background-image:
    repeating-linear-gradient(0deg,rgba(0,0,0,.05) 0 1px,transparent 1px 34px),
    repeating-linear-gradient(90deg,rgba(0,0,0,.05) 0 1px,transparent 1px 34px);
  overflow-x:hidden;
}

main{margin-left:206px;min-width:0}

a{color:inherit}

/* ---------- 左侧竖排导航 ---------- */
.rail{
  position:fixed;
  top:0;left:0;bottom:0;
  width:206px;
  display:flex;
  flex-direction:column;
  gap:12px;
  padding:16px 12px 18px;
  background:var(--blue);
  border-right:var(--line);
  z-index:20;
  overflow-y:auto;
}

.brand{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  width:56px;height:56px;
  flex:0 0 auto;
  background:#000;
  border:var(--line);
  box-shadow:4px 4px 0 #000;
  text-decoration:none;
}
.brand-mark{
  font-family:var(--ui);
  font-weight:700;
  font-size:26px;
  line-height:1;
  color:#fff;
}
.brand:hover{transform:translate(-2px,-2px);box-shadow:6px 6px 0 #000}

.rail-list{
  list-style:none;
  margin:4px 0 0;
  padding:0;
  display:flex;
  flex-direction:column;
  gap:6px;
}
.rail-list li{animation:rise .42s cubic-bezier(.2,.9,.32,1.4) both;animation-delay:calc(var(--d,0) * 45ms)}

.rail-list a,
.rail-cta{
  display:flex;
  align-items:center;
  gap:8px;
  min-height:44px;
  padding:6px 9px;
  font-family:var(--ui);
  font-size:16px;
  line-height:1.3;
  text-decoration:none;
  color:#000;
  border:3px solid transparent;
  transition:background .14s,box-shadow .14s,transform .14s,border-color .14s;
}
.rail-list a:hover,
.rail-list a:focus-visible,
.rail-list a.is-on{
  background:#fff;
  border-color:#000;
  box-shadow:3px 3px 0 #000;
  transform:translate(-2px,-2px);
}

.ico{
  width:10px;height:10px;
  flex:0 0 auto;
  background:#000;
  border:2px solid #000;
}

.rail-cta{
  margin-top:auto;
  background:var(--red);
  border-color:#000;
  box-shadow:3px 3px 0 #000;
  justify-content:flex-start;
}
.rail-cta:hover{transform:translate(-2px,-2px);box-shadow:5px 5px 0 #000}
.ico-dot{border-radius:50%}

/* ---------- 首屏 ---------- */
.hero{
  position:relative;
  min-height:100svh;
  display:flex;
  flex-direction:column;
  justify-content:center;
  align-items:flex-end;
  text-align:right;
  padding:100px clamp(20px,5vw,64px) 72px;
  border-bottom:var(--line);
  overflow:hidden;
}
.hero-bg{
  position:absolute;
  right:-.05em;
  bottom:-.14em;
  max-width:130%;
  font-family:var(--ui);
  font-weight:700;
  font-size:clamp(3.4rem,15vw,13rem);
  line-height:.85;
  letter-spacing:-.05em;
  color:rgba(59,177,255,.42);
  -webkit-text-stroke:2px #000;
  white-space:nowrap;
  pointer-events:none;
}
.hero-in{
  position:relative;
  z-index:1;
  max-width:660px;
}
.hero h1{
  display:inline-block;
  margin:0 0 20px;
  padding:10px 16px;
  font-family:var(--ui);
  font-weight:700;
  font-size:clamp(1.9rem,5.6vw,3.9rem);
  line-height:1.08;
  letter-spacing:-.02em;
  background:#fff;
  border:var(--line);
  box-shadow:var(--shadow);
}
.lede{
  margin:0 0 0 auto;
  max-width:44ch;
  font-size:clamp(1rem,1.6vw,1.16rem);
  line-height:1.7;
}

/* ---------- 内容区 ---------- */
.wrap{
  display:grid;
  grid-template-columns:196px minmax(0,1fr);
  align-items:start;
  gap:26px;
  max-width:1180px;
  margin:0 auto;
  padding:30px 24px 40px;
}

.side{
  position:sticky;
  top:20px;
  padding:14px 14px 18px;
  background:rgba(255,255,255,.66);
  backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  border:var(--line);
  border-radius:18px;
  box-shadow:var(--shadow);
}
.side h2{
  margin:0 0 8px;
  font-family:var(--ui);
  font-size:16px;
  line-height:1.3;
  letter-spacing:.14em;
}
hr{
  border:0;
  border-top:3px solid #000;
  margin:0 0 12px;
}
.side-list{
  list-style:none;
  margin:0;
  padding:0;
}
.side-list li + li{border-top:2px solid rgba(0,0,0,.16)}
.side-list a{
  display:block;
  padding:8px 4px;
  font-family:var(--ui);
  font-size:16px;
  line-height:1.4;
  text-decoration:none;
  color:#000;
}
.side-list a:hover{background:#fff;box-shadow:2px 2px 0 #000}

.body{min-width:0}

.prose section{
  margin:0 0 26px;
  padding:clamp(18px,3vw,34px);
  background:rgba(255,255,255,.62);
  backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  border:var(--line);
  border-radius:18px;
  box-shadow:var(--shadow);
  scroll-margin-top:24px;
}
.prose section:last-child{margin-bottom:0}

.prose h2{
  margin:0 0 12px;
  font-family:var(--ui);
  font-weight:700;
  font-size:clamp(1.4rem,2.6vw,2rem);
  line-height:1.24;
  letter-spacing:-.01em;
}
.prose h3{
  margin:26px 0 8px;
  font-family:var(--ui);
  font-weight:700;
  font-size:1.16rem;
  line-height:1.35;
}
.prose p{margin:0 0 14px}
.prose p:last-child{margin-bottom:0}
.prose a{
  color:#000;
  text-decoration:underline;
  text-decoration-thickness:3px;
  text-decoration-color:var(--red);
  text-underline-offset:3px;
}
.prose a:hover{background:var(--red)}
.prose ul,.prose ol{margin:0 0 14px;padding-left:1.3em}
.prose li{margin:0 0 8px}
.prose img{
  display:block;
  max-width:100%;
  height:auto;
  margin:14px 0;
  border:var(--line);
  border-radius:14px;
  box-shadow:4px 4px 0 #000;
}
.prose blockquote{
  margin:16px 0;
  padding:10px 16px;
  background:#fff;
  border:2px solid #000;
  border-left:8px solid var(--red);
}
.prose table{
  display:block;
  width:100%;
  overflow-x:auto;
  border-collapse:collapse;
  font-size:16px;
}
.prose th,.prose td{border:2px solid #000;padding:8px 10px;text-align:left}
.prose code{
  font-family:ui-monospace,SFMono-Regular,Menlo,monospace;
  font-size:.9em;
  background:#fff;
  border:2px solid #000;
  padding:1px 5px;
}

/* ---------- 页脚 ---------- */
.foot{
  max-width:1180px;
  margin:0 auto;
  padding:16px 24px 34px;
}
.foot-cta a{
  display:block;
  padding:clamp(14px,3vw,28px);
  text-align:center;
  text-decoration:none;
  font-family:var(--ui);
  font-weight:700;
  font-size:clamp(1.8rem,7vw,4.2rem);
  line-height:1.05;
  letter-spacing:-.02em;
  color:#000;
  background:var(--red);
  border:var(--line);
  box-shadow:8px 8px 0 #000;
  transition:transform .15s,box-shadow .15s;
}
.foot-cta a:hover{transform:translate(-3px,-3px);box-shadow:11px 11px 0 #000}

.foot-row{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  margin-top:24px;
  font-family:var(--ui);
  font-size:16px;
}
.foot-addr{font-style:normal}
.foot-links{
  list-style:none;
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  margin:0;
  padding:0;
}
.foot-links a{
  display:inline-flex;
  align-items:center;
  min-height:42px;
  padding:6px 13px;
  text-decoration:none;
  color:#000;
  background:#fff;
  border:3px solid #000;
  box-shadow:3px 3px 0 #000;
}
.foot-links a:hover{background:var(--blue)}

@keyframes rise{
  from{opacity:0;transform:translateY(10px)}
  to{opacity:1;transform:none}
}

/* ---------- 移动端 ---------- */
@media (max-width:900px){
  body{padding-bottom:80px}
  main{margin-left:0}
  .rail{
    top:auto;
    right:0;
    bottom:0;
    left:0;
    width:auto;
    max-width:100vw;
    flex-direction:row;
    align-items:center;
    gap:8px;
    padding:9px 10px;
    border-right:0;
    border-top:var(--line);
    overflow-x:auto;
    overflow-y:hidden;
  }
  .brand{width:48px;height:48px;box-shadow:3px 3px 0 #000}
  .brand-mark{font-size:22px}
  .rail-list{flex-direction:row;gap:8px;margin:0}
  .rail-list a,.rail-cta{white-space:nowrap;min-height:44px}
  .rail-cta{margin-top:0;margin-left:auto}
  .hero{min-height:88svh;padding:84px 18px 48px}
  .hero-bg{font-size:clamp(3rem,17vw,8rem);opacity:.9}
  .wrap{grid-template-columns:1fr;gap:18px;padding:20px 16px 24px}
  .side{position:static}
  .foot{padding:12px 16px 26px}
  .foot-row{flex-direction:column;align-items:flex-start;gap:10px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none !important;transition:none !important}
}

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