@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@400;500;700;900&display=swap');

:root{
  --paper:#fdfbf7;
  --stone:#f5f5f5;
  --ink:#1a1a1a;
  --rule:#e0e0e0;
  --rule-soft:#ececec;
  --rail:232px;
  --radius:18px;
}

*,*::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:"Outfit",-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  font-size:17px;
  line-height:1.75;
  letter-spacing:.01em;
  transition:none;
}

body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:0;
  pointer-events:none;
  opacity:.32;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)' opacity='0.32'/%3E%3C/svg%3E");
}

main,.foot{position:relative;z-index:1}

a{color:var(--ink)}

/* ---------- 左侧竖排导轨 ---------- */

.rail{
  position:fixed;
  inset:0 auto 0 0;
  width:var(--rail);
  z-index:20;
  display:flex;
  flex-direction:column;
  gap:26px;
  padding:30px 22px 22px;
  background:var(--paper);
  border-right:1px solid var(--ink);
}

.brand{
  display:block;
  font-size:22px;
  font-weight:900;
  letter-spacing:-.02em;
  line-height:1.15;
  text-decoration:none;
  padding:6px 0 12px;
  border-bottom:4px solid var(--ink);
  word-break:break-all;
}

.rail-nav{
  display:flex;
  flex-direction:column;
}

.rail-link{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:8px 4px;
  font-size:16px;
  font-weight:500;
  text-decoration:none;
  border-bottom:1px solid var(--rule-soft);
  transition:none;
}

.rail-link:hover,
.rail-link:focus-visible{
  background:var(--ink);
  color:var(--paper);
  padding-left:10px;
  outline:none;
}

/* ---------- 主体骨架 ---------- */

main{padding-left:var(--rail)}

.wrap{
  max-width:1140px;
  margin:0 auto;
  padding:0 34px 90px;
  display:grid;
  grid-template-columns:minmax(0,1fr) 246px;
  gap:44px;
  align-items:start;
}

.paper{min-width:0}

/* ---------- 首屏 ---------- */

.hero{
  position:relative;
  min-height:100vh;
  display:grid;
  grid-template-rows:1fr auto;
  gap:26px;
  padding:54px 0 46px;
  background-image:radial-gradient(rgba(26,26,26,.22) 1px, transparent 1px);
  background-size:17px 17px;
  background-position:0 0;
  border-bottom:1px solid var(--ink);
}

.hero-art{
  position:relative;
  min-height:48vh;
}

.ph{
  position:absolute;
  margin:0;
  border:1px solid var(--ink);
  border-radius:var(--radius);
  background:var(--stone);
  overflow:hidden;
  border-bottom-width:5px;
}

.ph-img,
.ph img{
  display:block;
  width:100%;
  height:100%;
  object-fit:cover;
}

.ph-a{
  left:0;
  top:4%;
  width:60%;
  aspect-ratio:4/5;
  transform:rotate(-2deg);
}

.ph-b{
  right:4%;
  bottom:0;
  width:54%;
  aspect-ratio:1/1;
  transform:rotate(2deg);
}

.hero-copy{
  text-align:right;
  padding-top:8px;
}

.hero-copy h1{
  margin:0;
  font-size:clamp(2.1rem,5.4vw,4.2rem);
  font-weight:900;
  line-height:1.06;
  letter-spacing:-.03em;
}

/* ---------- 正文 ---------- */

.doc{
  padding-top:6px;
  min-width:0;
}

.doc section[id]{
  scroll-margin-top:26px;
}

.doc h2{
  margin:66px 0 14px;
  font-size:clamp(1.45rem,3.2vw,2.05rem);
  font-weight:900;
  line-height:1.22;
  letter-spacing:-.02em;
}

.doc h3{
  margin:38px 0 12px;
  font-size:1.22rem;
  font-weight:700;
  line-height:1.35;
}

.doc p{margin:0 0 20px}

.doc ul,
.doc ol{
  margin:0 0 22px;
  padding-left:1.35em;
}

.doc li{margin:0 0 10px}

.doc a{
  text-decoration:underline;
  text-decoration-thickness:1px;
  text-underline-offset:3px;
}

.doc a:hover{
  background:var(--ink);
  color:var(--paper);
  text-decoration:none;
}

.doc strong{font-weight:700}

.doc blockquote{
  margin:0 0 26px;
  padding:18px 22px;
  background:var(--stone);
  border:1px solid var(--ink);
  border-left-width:9px;
  border-radius:var(--radius);
}

.doc blockquote p:last-child{margin-bottom:0}

.doc table{
  width:100%;
  border-collapse:collapse;
  margin:0 0 26px;
  font-size:16px;
}

.doc th,
.doc td{
  padding:12px;
  text-align:left;
  border-bottom:1px solid var(--rule);
  vertical-align:top;
}

.doc th{
  font-weight:700;
  border-bottom:1px solid var(--ink);
}

.doc img{
  max-width:100%;
  height:auto;
  border-radius:var(--radius);
}

.doc figure{margin:0 0 26px}

.doc hr{
  border:0;
  border-top:1px solid var(--ink);
  margin:0 0 26px;
}

.doc h2 + hr,
.doc h3 + hr{margin-top:0}

.doc section:first-of-type h2{margin-top:54px}

/* ---------- 侧栏 ---------- */

.side{
  position:sticky;
  top:26px;
  margin-top:56px;
  padding:20px 20px 22px;
  background:var(--stone);
  border:1px solid var(--rule);
  border-bottom:5px solid var(--ink);
  border-radius:var(--radius);
}

.side h2{
  margin:0 0 10px;
  font-size:16px;
  font-weight:900;
  letter-spacing:.16em;
  text-transform:uppercase;
}

.side hr{
  border:0;
  border-top:1px solid var(--ink);
  margin:0 0 12px;
}

.side-list{
  list-style:none;
  margin:0 0 14px;
  padding:0;
}

.side-list li{border-bottom:1px solid var(--rule)}

.side-list a{
  display:flex;
  align-items:center;
  min-height:40px;
  padding:8px 2px;
  font-size:16px;
  text-decoration:none;
}

.side-list a:hover{background:var(--ink);color:var(--paper)}

.side-top{
  display:inline-flex;
  align-items:center;
  min-height:40px;
  padding:0 2px;
  font-size:16px;
  font-weight:700;
  text-decoration:none;
  border-bottom:2px solid var(--ink);
}

/* ---------- 页脚 ---------- */

.foot{
  margin-left:var(--rail);
  padding:56px 34px 30px;
  border-top:1px solid var(--ink);
  background:var(--paper);
}

.foot-brand{
  margin:0;
  font-size:clamp(2.4rem,9vw,5.6rem);
  font-weight:900;
  line-height:1;
  letter-spacing:-.045em;
}

.foot-cols{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:30px;
  max-width:760px;
  margin:40px 0 0;
}

.foot-cols dl{margin:0}

.foot-cols dt{
  font-size:16px;
  font-weight:900;
  letter-spacing:.16em;
  padding-bottom:7px;
  margin-bottom:4px;
  border-bottom:1px solid var(--ink);
}

.foot-cols dd{margin:0}

.foot-cols a{
  display:flex;
  align-items:center;
  min-height:40px;
  padding:8px 0;
  font-size:16px;
  text-decoration:none;
}

.foot-cols a:hover{
  background:var(--ink);
  color:var(--paper);
  padding-left:8px;
}

.foot-copy{
  margin:42px 0 0;
  padding-top:16px;
  font-size:16px;
  border-top:1px solid var(--rule);
}

/* ---------- 移动端 ---------- */

@media (max-width:960px){
  .rail{
    position:sticky;
    inset:auto;
    top:0;
    width:auto;
    flex-direction:row;
    align-items:center;
    gap:6px;
    padding:0 14px;
    border-right:0;
    border-bottom:1px solid var(--ink);
    overflow-x:auto;
  }

  .brand{
    flex:0 0 auto;
    font-size:18px;
    padding:12px 0;
    border-bottom:0;
    white-space:nowrap;
  }

  .rail-nav{
    flex-direction:row;
    gap:2px;
    margin-left:auto;
  }

  .rail-link{
    min-height:44px;
    padding:10px 11px;
    white-space:nowrap;
    border-bottom:0;
  }

  .rail-link:hover,
  .rail-link:focus-visible{padding-left:11px}

  main{padding-left:0}

  .wrap{
    grid-template-columns:1fr;
    gap:0;
    padding:0 18px 56px;
  }

  .hero{
    min-height:0;
    grid-template-rows:auto auto;
    padding:26px 0 30px;
  }

  .hero-copy{
    order:-1;
    padding-top:0;
  }

  .hero-copy h1{font-size:clamp(1.9rem,8vw,2.6rem)}

  .hero-art{
    min-height:44vh;
    margin-top:22px;
  }

  .ph-a{width:62%;top:2%}
  .ph-b{width:52%}

  .doc section[id]{scroll-margin-top:78px}

  .doc h2{margin-top:48px}

  .doc section:first-of-type h2{margin-top:40px}

  .side{
    position:static;
    margin-top:44px;
  }

  .foot{
    margin-left:0;
    padding:40px 18px 26px;
  }

  .foot-cols{
    gap:14px;
    margin-top:30px;
  }

  .foot-cols dt{
    font-size:16px;
    letter-spacing:.08em;
  }

  .foot-cols a{font-size:16px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
}

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