@import url('https://fonts.googleapis.com/css2?family=Archivo:wght@300;400;500;600;700&family=Space+Grotesk:wght@300;400;500;600;700&display=swap');

:root{
  --ink:#000000;
  --paper:#ffffff;
  --pad:clamp(18px,5vw,64px);
  --rule:1px solid #000000;
  --r:10px;
}

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

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

body{
  margin:0;
  padding-bottom:108px;
  background:var(--paper);
  color:var(--ink);
  font-family:'Space Grotesk','Helvetica Neue',system-ui,-apple-system,sans-serif;
  font-size:17px;
  line-height:1.68;
  font-weight:400;
  letter-spacing:.004em;
}

img{max-width:100%;display:block}

h1,h2,h3,h4{
  font-family:'Archivo','Helvetica Neue',system-ui,sans-serif;
  font-weight:600;
  line-height:1.06;
  letter-spacing:-.02em;
  margin:0;
}

p{margin:0 0 1em}

a{color:inherit}

a:focus-visible,
button:focus-visible{
  outline:2px solid #000;
  outline-offset:3px;
}

/* ---------- 角落品牌图标 ---------- */
.mark{
  position:fixed;
  top:0;
  left:0;
  z-index:80;
  display:flex;
  align-items:center;
  justify-content:center;
  min-width:58px;
  min-height:58px;
  padding:10px 14px;
  background:var(--paper);
  border-right:var(--rule);
  border-bottom:var(--rule);
  text-decoration:none;
  max-width:min(52vw,260px);
  overflow:hidden;
}
.mark img{height:26px;width:auto;filter:grayscale(1)}
.mark-txt{
  font-family:'Archivo',sans-serif;
  font-weight:700;
  font-size:12px;
  letter-spacing:.12em;
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
}

/* ---------- 主栅格 ---------- */
.stage{padding:0 var(--pad)}

@media (min-width:900px){
  .stage{
    display:grid;
    grid-template-columns:minmax(0,1fr) 244px;
    gap:clamp(28px,5vw,80px);
    align-items:start;
  }
}

main{min-width:0}

/* ---------- 头版 ---------- */
.masthead{
  position:relative;
  overflow:hidden;
  min-height:70vh;
  display:flex;
  flex-direction:column;
  justify-content:center;
  padding:clamp(76px,15vh,150px) 0 clamp(26px,5vw,48px);
  border-bottom:var(--rule);
}

.masthead h1{
  font-size:clamp(33px,7vw,84px);
  font-weight:600;
  max-width:16ch;
  text-wrap:balance;
}

.deco{
  position:absolute;
  right:-.05em;
  bottom:-.16em;
  font-family:'Archivo',sans-serif;
  font-weight:700;
  font-size:clamp(120px,30vw,340px);
  line-height:.74;
  letter-spacing:-.07em;
  opacity:.07;
  pointer-events:none;
  user-select:none;
}

.dek{
  max-width:44ch;
  margin-top:clamp(14px,2.4vw,22px);
  margin-bottom:0;
  font-size:clamp(16px,1.35vw,19px);
  line-height:1.6;
  opacity:.8;
}

.hero-fig{margin:clamp(26px,5vw,46px) 0 0}
.hero-fig img{
  width:100%;
  height:clamp(180px,30vh,340px);
  object-fit:cover;
  filter:grayscale(1);
  border-radius:var(--r);
}

/* ---------- 目录分栏标 ---------- */
.index-head{
  display:flex;
  align-items:center;
  gap:clamp(12px,3vw,24px);
  padding:clamp(24px,4vw,42px) 0 clamp(12px,2vw,18px);
}
.index-head h2{
  font-size:12px;
  font-weight:500;
  letter-spacing:.28em;
  text-transform:uppercase;
  white-space:nowrap;
}
.index-head hr{
  flex:1;
  margin:0;
  border:0;
  border-top:var(--rule);
}

/* ---------- 正文卡片 ---------- */
.sheet{display:block}

.sheet > section{
  background:var(--paper);
  border:var(--rule);
  border-radius:var(--r);
  padding:clamp(22px,3.4vw,42px);
  margin:0 0 clamp(16px,2.6vw,26px);
  box-shadow:0 16px 36px -28px rgba(0,0,0,.6);
  scroll-margin-top:84px;
  transition:box-shadow .35s ease,transform .35s ease;
}
.sheet > section:hover{
  transform:translateY(-3px);
  box-shadow:0 24px 52px -28px rgba(0,0,0,.6);
}

.sheet > section h2{
  font-size:clamp(23px,3.3vw,38px);
  margin:0 0 .38em;
  text-wrap:balance;
}
.sheet > section h2 + hr{
  border:0;
  border-top:var(--rule);
  margin:0 0 1.15em;
}
.sheet > section h3{
  font-size:clamp(18px,2.3vw,24px);
  margin:1.5em 0 .45em;
}
.sheet > section h3 + hr{
  border:0;
  border-top:var(--rule);
  margin:0 0 1em;
}

.sheet > section:first-of-type > p:first-of-type::first-letter{
  float:left;
  font-family:'Archivo',sans-serif;
  font-weight:700;
  font-size:3.5em;
  line-height:.8;
  padding:.05em .1em 0 0;
}

.sheet blockquote{
  margin:1.5em 0;
  padding:0 0 0 clamp(14px,2.4vw,26px);
  border-left:4px solid #000;
  font-family:'Archivo',sans-serif;
  font-weight:300;
  font-size:clamp(19px,2.5vw,26px);
  line-height:1.34;
  letter-spacing:-.012em;
}
.sheet blockquote p:last-child{margin-bottom:0}

.sheet ul,.sheet ol{padding-left:1.25em;margin:0 0 1em}
.sheet li{margin:.36em 0}
.sheet strong{font-weight:600}
.sheet figure{margin:1.4em 0}
.sheet figcaption{font-size:14px;letter-spacing:.04em;opacity:.7;margin-top:.5em}
.sheet a{text-decoration:underline;text-underline-offset:3px}

@media (min-width:1040px){
  .sheet > section > p{
    columns:19rem;
    column-gap:2.4rem;
  }
  .sheet > section > p:first-of-type{columns:auto}
}

/* ---------- 侧栏 / 全屏菜单 ---------- */
.rail{padding:clamp(24px,4vw,42px) 0}

@media (max-width:899px){
  .rail{display:none}
}

@media (min-width:900px){
  .rail{
    position:sticky;
    top:0;
    max-height:100vh;
    overflow:auto;
  }
}

.rail-title{
  margin:0 0 10px;
  font-family:'Archivo',sans-serif;
  font-size:12px;
  font-weight:500;
  letter-spacing:.28em;
  text-transform:uppercase;
}

.rail nav ul{list-style:none;margin:0;padding:0}

.rail nav a{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:10px 2px;
  font-size:16px;
  line-height:1.4;
  text-decoration:none;
  border-bottom:var(--rule);
  transition:padding-left .25s ease;
}
.rail nav a:hover,
.rail nav a:focus-visible{padding-left:10px}

body.menu-open{overflow:hidden}

body.menu-open .rail{
  display:block;
  position:fixed;
  inset:0;
  z-index:90;
  max-height:none;
  overflow:auto;
  background:var(--paper);
  border-left:0;
  padding:98px var(--pad) 130px;
}
body.menu-open .rail nav a{
  font-family:'Archivo',sans-serif;
  font-weight:500;
  font-size:clamp(22px,4.4vw,38px);
  letter-spacing:-.02em;
  min-height:66px;
  padding:12px 2px;
}

/* ---------- 底部固定条 ---------- */
.dock{
  position:fixed;
  left:0;
  right:0;
  bottom:0;
  z-index:95;
  display:flex;
  justify-content:center;
  padding:10px 14px;
  background:rgba(255,255,255,.94);
  border-top:var(--rule);
  backdrop-filter:blur(8px);
}

.burger{
  min-height:48px;
  min-width:132px;
  padding:0 26px;
  border-radius:999px;
  border:var(--rule);
  background:#000;
  color:#fff;
  font:inherit;
  font-size:16px;
  font-weight:500;
  letter-spacing:.24em;
  text-indent:.24em;
  cursor:pointer;
  transition:background .25s ease,color .25s ease;
}
.burger:hover{background:#fff;color:#000}

/* ---------- 页脚 ---------- */
.foot{
  display:grid;
  grid-template-columns:1fr;
  gap:14px;
  margin-top:clamp(28px,6vw,64px);
  padding:clamp(30px,6vw,62px) var(--pad) 30px;
  border-top:var(--rule);
  text-align:center;
}

@media (min-width:760px){
  .foot{
    grid-template-columns:1.5fr 1fr 1fr;
    align-items:end;
    gap:clamp(16px,4vw,40px);
  }
}

.foot-mark{
  margin:0;
  font-family:'Archivo',sans-serif;
  font-weight:700;
  font-size:clamp(23px,4.4vw,54px);
  line-height:.94;
  letter-spacing:-.04em;
  text-align:left;
}

.foot-mid{
  margin:0;
  font-size:14px;
  letter-spacing:.22em;
}

.foot-copy{font-size:13px;letter-spacing:.05em}

/* ---------- 动效 ---------- */
@media (prefers-reduced-motion: no-preference){
  .js .sheet > section.reveal{
    opacity:0;
    transform:translateY(16px);
    transition:opacity .6s ease,transform .6s cubic-bezier(.22,.7,.3,1),box-shadow .35s ease;
  }
  .js .sheet > section.reveal.in{
    opacity:1;
    transform:none;
  }
  .js .sheet > section.reveal.in:hover{transform:translateY(-3px)}
}

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  .sheet > section,
  .rail nav a,
  .burger{transition:none}
}

@media (max-width:420px){
  .deck{}
  .foot-mark{text-align:left}
  .mark-txt{font-size:11px}
}

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