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

:root{
  --ink:#000;
  --paper:#fff;
  --ash:#f2f2f2;
  --line:#dcdcdc;
  --mute:#5c5c5c;
  --serif:'Playfair Display',"Songti SC","Times New Roman",Georgia,serif;
  --sans:'Inter',-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
}

*,*::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:var(--sans);
  font-size:17px;
  line-height:1.72;
  letter-spacing:.012em;
  font-weight:400;
  overflow-x:hidden;
}

img{max-width:100%;height:auto;display:block}
a{color:inherit}
h1,h2,h3{font-family:var(--serif);font-weight:600;line-height:1.12;letter-spacing:-.012em;margin:0}
hr{border:0;border-top:1px solid var(--line);margin:16px 0 0}
code,kbd,pre{font-family:'SFMono-Regular',Consolas,monospace;font-size:.92em}

.page-mark{display:none}

/* ---------- 底部固定条 ---------- */
.dock{
  position:fixed;
  left:0;right:0;bottom:0;
  z-index:50;
  display:flex;
  align-items:center;
  gap:8px;
  padding:9px 14px calc(9px + env(safe-area-inset-bottom));
  background:var(--ink);
  color:var(--paper);
  border-top:1px solid #2e2e2e;
}

.dock-mark{
  flex:0 0 auto;
  display:grid;
  place-items:center;
  width:44px;height:44px;
  border:1px solid #484848;
  border-radius:10px;
  text-decoration:none;
  color:var(--paper);
  font-family:var(--serif);
  font-size:20px;
  line-height:1;
  transition:border-color .25s ease,background .25s ease,color .25s ease;
}
.dock-mark:hover{background:var(--paper);color:var(--ink);border-color:var(--paper)}
.mark-img{width:26px;height:26px;object-fit:contain;filter:invert(1)}
.dock-mark:hover .mark-img{filter:none}

.dock-nav{
  margin-left:auto;
  display:flex;
  gap:8px;
  min-width:0;
}

.fold{position:relative}
.fold-tab{
  list-style:none;
  cursor:pointer;
  display:flex;
  align-items:center;
  min-height:44px;
  padding:0 15px;
  border-radius:10px;
  background:#1b1b1b;
  color:var(--paper);
  font-size:16px;
  letter-spacing:.06em;
  user-select:none;
  transition:background .2s ease,color .2s ease;
}
.fold-tab::-webkit-details-marker{display:none}
.fold-tab::marker{content:''}
.fold-tab:hover{background:#2c2c2c}
.fold[open] .fold-tab{background:var(--paper);color:var(--ink)}

.fold-sheet{
  position:absolute;
  right:0;
  bottom:calc(100% + 10px);
  width:212px;
  display:flex;
  flex-direction:column;
  padding:6px;
  background:var(--paper);
  color:var(--ink);
  border-radius:10px;
  box-shadow:0 20px 44px rgba(0,0,0,.4);
}
.fold-link{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:0 12px;
  border-radius:8px;
  text-decoration:none;
  font-size:16px;
  transition:background .18s ease;
}
.fold-link:hover{background:var(--ash)}

.dock-cta{
  flex:0 0 auto;
  margin-left:6px;
  display:flex;
  align-items:center;
  min-height:44px;
  padding:0 17px;
  border-radius:10px;
  background:var(--paper);
  color:var(--ink);
  text-decoration:none;
  font-weight:600;
  font-size:16px;
  letter-spacing:.03em;
  transition:transform .2s ease,opacity .2s ease;
}
.dock-cta:hover{transform:translateY(-2px)}

/* ---------- 头图 ---------- */
.stage{display:block}

.hero{
  position:relative;
  isolation:isolate;
  display:flex;
  flex-direction:column;
  justify-content:flex-end;
  min-height:100vh;
  min-height:100svh;
  padding:clamp(18px,5vw,56px);
  padding-bottom:clamp(70px,15vh,160px);
  background:var(--ink);
  color:var(--paper);
  clip-path:polygon(0 0,100% 0,100% 91%,0 100%);
  overflow:hidden;
}

.hero-frame{
  position:absolute;
  inset:0;
  margin:0;
  z-index:-2;
}
.hero-img{
  width:100%;
  height:100%;
  object-fit:cover;
  object-position:center 32%;
  filter:grayscale(1) contrast(1.18) brightness(.68);
  opacity:.9;
}
.hero::after{
  content:"";
  position:absolute;
  inset:0;
  z-index:-1;
  background:linear-gradient(185deg,rgba(0,0,0,.1),rgba(0,0,0,.88));
}

.hero-badge{
  position:absolute;
  top:clamp(22px,7vw,70px);
  left:clamp(16px,4vw,48px);
  transform:rotate(-7deg);
  padding:9px 15px;
  border-radius:10px;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--serif);
  font-size:14px;
  letter-spacing:.18em;
  line-height:1.3;
}

.hero-slab{
  margin-left:auto;
  max-width:66ch;
  text-align:right;
}
.hero-h1{
  font-size:clamp(30px,7.2vw,74px);
  margin-bottom:16px;
  text-wrap:balance;
}
.hero-desc{
  display:inline-block;
  margin:0;
  max-width:46ch;
  font-size:clamp(15px,1.7vw,18px);
  line-height:1.66;
  color:#e8e8e8;
  border-right:3px solid var(--paper);
  padding-right:14px;
}

/* ---------- 主体网格 ---------- */
.shell{
  display:grid;
  grid-template-columns:minmax(0,208px) minmax(0,1fr);
  gap:clamp(22px,4.4vw,64px);
  max-width:1180px;
  margin:0 auto;
  padding:clamp(30px,6vw,78px) clamp(16px,4vw,40px) clamp(44px,8vw,90px);
}

.rail{
  align-self:start;
  position:sticky;
  top:24px;
}
.rail-title{
  font-size:20px;
  letter-spacing:-.01em;
}
.rail hr{margin-top:12px;border-top-width:2px;border-color:var(--ink)}
.rail-list{
  list-style:none;
  margin:18px 0 0;
  padding:0;
  display:flex;
  flex-direction:column;
}
.rail-list a{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:6px 0;
  font-size:16px;
  text-decoration:none;
  border-bottom:1px solid var(--line);
  transition:padding-left .2s ease,border-color .2s ease;
}
.rail-list a:hover{padding-left:8px;border-color:var(--ink)}

/* ---------- 正文 ---------- */
.prose{min-width:0}
.prose > article{
  padding:clamp(26px,4vw,50px) 0;
  border-top:1px solid var(--line);
  scroll-margin-top:22px;
}
.prose > article:first-child{border-top:0;padding-top:0}
.prose > article:last-child{padding-bottom:0}

.prose h2{font-size:clamp(23px,3.4vw,38px);text-wrap:balance}
.prose h3{font-size:clamp(19px,2.2vw,24px);margin-top:26px}
.prose h2 + hr{margin:14px 0 22px;border-color:var(--ink)}
.prose h3 + hr{margin:12px 0 16px}

.prose p{margin:0 0 18px;max-width:64ch}
.prose p:last-child{margin-bottom:0}

.prose > article:first-child > p:first-of-type::first-letter{
  float:left;
  font-family:var(--serif);
  font-size:3.5em;
  line-height:.84;
  padding:6px 12px 0 0;
}

.prose blockquote{
  margin:28px 0;
  padding:6px 0 6px 22px;
  border-left:4px solid var(--ink);
  font-family:var(--serif);
  font-size:1.16em;
  line-height:1.5;
  max-width:52ch;
}
.prose blockquote p{max-width:none}

.prose figure{margin:28px 0}
.prose figure img{border-radius:10px}
.prose figcaption{margin-top:8px;font-size:14px;line-height:1.5;color:var(--mute)}

.prose ul,.prose ol{margin:0 0 20px;padding-left:1.25em;max-width:62ch}
.prose li{margin-bottom:9px}
.prose strong{font-weight:600}
.prose a{text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}

.prose table{
  width:100%;
  border-collapse:collapse;
  margin:0 0 20px;
  font-size:16px;
}
.prose th,.prose td{
  padding:10px 12px;
  border-bottom:1px solid var(--line);
  text-align:left;
}
.prose pre{
  overflow-x:auto;
  padding:14px 16px;
  border-radius:10px;
  background:var(--ash);
  margin:0 0 20px;
}

/* ---------- 页脚 ---------- */
.colophon{
  background:var(--ink);
  color:var(--paper);
  padding:clamp(38px,7vw,78px) clamp(16px,4vw,40px) calc(104px + env(safe-area-inset-bottom));
}
.colophon > article{
  max-width:1180px;
  margin:0 auto;
}
.colophon h2{font-size:clamp(26px,5vw,48px);text-wrap:balance}
.colophon hr{border-color:#333;margin-top:16px}

.col-cta{padding-bottom:clamp(26px,4vw,44px)}
.col-cta-btn{
  display:inline-flex;
  align-items:center;
  min-height:48px;
  margin-top:24px;
  padding:0 24px;
  border-radius:10px;
  background:var(--paper);
  color:var(--ink);
  text-decoration:none;
  font-weight:600;
  font-size:16px;
  transition:transform .2s ease;
}
.col-cta-btn:hover{transform:translateY(-2px)}

.col-index{
  border-top:1px solid #333;
  padding:clamp(20px,3vw,32px) 0;
}
.col-nav dl{margin:0;max-width:640px}
.col-nav dt{
  font-family:var(--serif);
  font-size:15px;
  letter-spacing:.16em;
  color:#8d8d8d;
  margin:14px 0 6px;
}
.col-nav dt:first-child{margin-top:0}
.col-nav dd{margin:0}
.col-nav a{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:4px 0;
  font-size:16px;
  text-decoration:none;
  border-bottom:1px solid #2f2f2f;
  transition:border-color .2s ease,padding-left .2s ease;
}
.col-nav a:hover{border-color:var(--paper);padding-left:6px}

.col-meta{
  display:flex;
  flex-wrap:wrap;
  gap:10px 16px;
  align-items:center;
  justify-content:space-between;
  border-top:1px solid #333;
  padding-top:18px;
  margin-top:10px;
  font-size:15px;
}
.col-brand{margin:0;color:#9a9a9a;letter-spacing:.06em}
.col-top{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:0 4px;
  text-decoration:none;
  border-bottom:1px solid #4a4a4a;
}

/* ---------- 动效 ---------- */
.reveal{opacity:0;transform:translateY(18px);transition:opacity .7s ease,transform .7s ease}
.reveal.in{opacity:1;transform:none}

/* ---------- 响应式 ---------- */
@media (min-width:820px){
  .colophon{
    display:grid;
    grid-template-columns:1.5fr 1fr 0.9fr;
    gap:clamp(24px,4vw,60px);
    align-items:start;
  }
  .colophon > article{margin:0}
  .col-cta{grid-column:1;padding-bottom:0}
  .col-index{grid-column:2;border-top:0;padding:0}
  .col-nav a{display:inline-flex;border-bottom:0;text-decoration:underline;text-underline-offset:3px;text-decoration-color:#4a4a4a}
  .col-nav a:hover{text-decoration-color:var(--paper)}
  .col-meta{
    grid-column:1 / -1;
    margin-top:clamp(20px,4vw,44px);
    border-top:1px solid #333;
  }
}

@media (max-width:819px){
  .shell{grid-template-columns:minmax(0,1fr)}
  .rail{position:static}
  .rail-list{
    flex-direction:row;
    flex-wrap:wrap;
    gap:8px;
    margin-top:16px;
  }
  .rail-list a{
    min-height:44px;
    padding:0 12px;
    border:1px solid var(--line);
    border-radius:10px;
    font-size:15px;
  }
  .rail-list a:hover{padding-left:12px;border-color:var(--ink)}
  .prose > article:first-child > p:first-of-type::first-letter{font-size:3em}
}

@media (max-width:430px){
  .hero{padding-bottom:clamp(60px,13vh,120px)}
  .hero-desc{font-size:15px;padding-right:10px}
  .dock{gap:6px;padding-left:10px;padding-right:10px}
  .fold-tab{padding:0 12px}
  .dock-cta{padding:0 13px}
  .fold-sheet{width:190px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *{animation-duration:.001ms !important;transition-duration:.001ms !important}
  .reveal{opacity:1;transform:none}
}

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