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

:root{
  --paper:#ffffff;
  --mist:#f5f5f5;
  --ink:#1f1f1f;
  --ink-2:#4d4d4d;
  --ink-3:#8a8a8a;
  --line:rgba(31,31,31,.14);
  --line-2:rgba(31,31,31,.07);
  --r:4px;
  --dock-h:66px;
  --el-1:0 1px 2px rgba(31,31,31,.07);
  --el-2:0 4px 14px rgba(31,31,31,.09);
  --el-3:0 12px 30px rgba(31,31,31,.13);
  --el-4:0 22px 56px rgba(31,31,31,.2);
  --font:"Poppins","Open Sans",system-ui,-apple-system,"Segoe UI",Roboto,"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;
  font-family:var(--font);
  font-size:17px;
  line-height:1.72;
  color:var(--ink);
  background-color:var(--mist);
  background-image:radial-gradient(rgba(31,31,31,.055) 1px,transparent 1px);
  background-size:26px 26px;
  padding-bottom:calc(var(--dock-h) + 30px + env(safe-area-inset-bottom,0px));
  overflow-x:hidden;
  overflow-x:clip;
}

a{color:inherit}
img{display:block;max-width:100%;height:auto}
p{margin:0 0 1em}

/* ---------- hero ---------- */
.hero{
  position:relative;
  display:grid;
  grid-template-columns:minmax(0,.95fr) minmax(0,1.05fr);
  align-items:center;
  gap:clamp(24px,5vw,80px);
  min-height:100vh;
  min-height:100svh;
  padding:clamp(56px,9vh,110px) clamp(18px,4.5vw,72px) clamp(100px,15vh,160px);
  perspective:1400px;
  background-image:radial-gradient(rgba(31,31,31,.17) 1.2px,transparent 1.2px);
  background-size:24px 24px;
  background-position:center;
}

.hero::after{
  content:"";
  position:absolute;
  inset:0;
  z-index:0;
  pointer-events:none;
  background:linear-gradient(180deg,rgba(245,245,245,.9),rgba(245,245,245,.38) 46%,rgba(245,245,245,.94));
}

.hero > *{position:relative;z-index:1}

.hero-stack{
  position:relative;
  z-index:1;
  margin:0;
  width:100%;
  max-width:430px;
  aspect-ratio:4/5;
  transform-style:preserve-3d;
  transition:transform .6s cubic-bezier(.2,.7,.3,1);
}

.hero-stack .layer{
  position:absolute;
  inset:0;
  border-radius:10px;
  border:1px solid var(--line);
  background:var(--paper);
}

.hero-stack .l1{
  transform:translate3d(-18px,20px,-42px) rotate(-3deg);
  background:var(--mist);
  box-shadow:var(--el-2);
}

.hero-stack .l2{
  transform:translate3d(-9px,10px,-20px) rotate(-1.5deg);
  box-shadow:var(--el-3);
}

.hero-stack .l3{
  overflow:hidden;
  box-shadow:var(--el-4);
  background-image:radial-gradient(rgba(31,31,31,.12) 1px,transparent 1px);
  background-size:18px 18px;
  z-index:3;
}

.hero-stack .hero-img{
  width:100%;
  height:100%;
  object-fit:cover;
}

.hero-copy{
  position:relative;
  z-index:2;
  max-width:640px;
  margin-left:auto;
  text-align:right;
}

.kicker{
  margin:0 0 14px;
  font-size:13px;
  letter-spacing:.24em;
  font-weight:600;
  color:var(--ink-2);
}

.hero-copy h1{
  margin:0 0 18px;
  font-size:clamp(30px,4.6vw,58px);
  line-height:1.14;
  font-weight:600;
  letter-spacing:-.025em;
}

.lede{
  max-width:46ch;
  margin-left:auto;
  margin-bottom:26px;
  color:var(--ink-2);
  font-size:17px;
}

.cta{
  display:flex;
  flex-wrap:wrap;
  gap:12px;
  justify-content:flex-end;
}

.pill{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:0 22px;
  border-radius:999px;
  border:1px solid var(--ink);
  background:var(--paper);
  color:var(--ink);
  font-size:16px;
  text-decoration:none;
  box-shadow:var(--el-1);
  transition:transform .25s,box-shadow .25s,background .25s,color .25s;
}

.pill:hover{transform:translateY(-2px);box-shadow:var(--el-2)}
.pill.solid{background:var(--ink);color:#fff}
.pill.solid:hover{background:#000}

/* ---------- 正文 + 侧栏 ---------- */
.stage{
  display:grid;
  grid-template-columns:minmax(0,1fr) 292px;
  align-items:start;
  gap:clamp(20px,3vw,40px);
  max-width:1180px;
  margin:0 auto;
  padding:clamp(34px,5vw,76px) clamp(16px,4vw,48px);
}

.prose{
  min-width:0;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--r);
  padding:clamp(20px,3.4vw,48px);
}

.prose > article{
  padding:clamp(18px,2.8vw,30px) 0;
  border-bottom:1px solid var(--line-2);
  scroll-margin-top:28px;
  scroll-margin-bottom:calc(var(--dock-h) + 28px);
}

.prose > article:first-child{padding-top:0}
.prose > article:last-child{border-bottom:0;padding-bottom:0}

.prose h2{
  display:flex;
  align-items:baseline;
  gap:12px;
  margin:0 0 .6em;
  font-size:clamp(21px,2.5vw,29px);
  line-height:1.3;
  font-weight:600;
  letter-spacing:-.012em;
}

.prose h2::before{
  content:"";
  flex:0 0 auto;
  width:9px;
  height:9px;
  border-radius:2px;
  background:var(--ink);
  transform:translateY(-3px);
}

.prose h3{
  margin:1.1em 0 .5em;
  font-size:clamp(18px,2vw,21px);
  line-height:1.4;
  font-weight:600;
}

.prose h3::before{
  content:"";
  display:inline-block;
  width:14px;
  height:2px;
  background:var(--ink);
  vertical-align:middle;
  margin-right:10px;
  transform:translateY(-1px);
}

.prose ul,.prose ol{margin:0 0 1em;padding-left:1.35em}
.prose li{margin:.34em 0}

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

.prose a:hover{background:var(--mist)}

.prose img{
  margin:1.1em 0;
  border-radius:var(--r);
  border:1px solid var(--line);
}

.prose blockquote{
  margin:1.2em 0;
  padding:.55em 0 .55em 1.1em;
  border-left:3px solid var(--ink);
  color:var(--ink-2);
}

.prose table{
  width:100%;
  display:block;
  overflow-x:auto;
  border-collapse:collapse;
  margin:0 0 1em;
  font-size:16px;
}

.prose th,.prose td{
  border:1px solid var(--line);
  padding:8px 10px;
  text-align:left;
}

.prose strong{font-weight:600}

.rail{
  position:sticky;
  top:24px;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--r);
  padding:16px 14px;
  box-shadow:var(--el-1);
}

.rail h2{
  display:flex;
  align-items:center;
  gap:8px;
  margin:0 0 10px;
  padding-left:2px;
  font-size:13px;
  font-weight:600;
  letter-spacing:.2em;
  color:var(--ink-3);
}

.rail h2::after{
  content:"";
  flex:1 1 auto;
  height:1px;
  background:var(--line);
}

.rail-list{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:2px;
}

.rail-list a{
  display:flex;
  align-items:center;
  gap:10px;
  min-height:42px;
  padding:4px 8px;
  border-radius:var(--r);
  font-size:16px;
  line-height:1.4;
  color:var(--ink-2);
  text-decoration:none;
  transition:background .2s,color .2s;
}

.rail-list a:hover{background:var(--mist);color:var(--ink)}

.idx{
  flex:0 0 auto;
  font-size:12px;
  letter-spacing:.08em;
  color:var(--ink-3);
  font-variant-numeric:tabular-nums;
}

.rail-name{min-width:0}

/* ---------- 页脚 ---------- */
.site-foot{
  background:var(--ink);
  color:#f5f5f5;
  padding:clamp(34px,6vw,72px) clamp(18px,4vw,64px) calc(var(--dock-h) + 40px + env(safe-area-inset-bottom,0px));
  display:flex;
  flex-wrap:wrap;
  align-items:flex-start;
  justify-content:space-between;
  gap:clamp(26px,5vw,64px);
}

.foot-brand{flex:1 1 300px;min-width:0}

.foot-mark{
  margin:0;
  font-size:clamp(34px,6.4vw,76px);
  line-height:1;
  font-weight:600;
  letter-spacing:-.035em;
  color:#fff;
  word-break:break-word;
}

.foot-mark a{
  display:inline-block;
  color:#fff;
  text-decoration:none;
  transition:transform .3s;
}

.foot-mark a:hover{transform:translateY(-4px)}

.foot-nav{flex:1 1 320px;min-width:0}

.foot-nav dl{
  margin:0;
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:8px 14px;
  align-items:baseline;
}

.foot-nav dt{
  font-size:12px;
  letter-spacing:.14em;
  color:#8f8f8f;
  font-variant-numeric:tabular-nums;
}

.foot-nav dd{margin:0}

.foot-nav a{
  display:inline-flex;
  align-items:center;
  min-height:40px;
  font-size:16px;
  color:#ededed;
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:border-color .2s,color .2s;
}

.foot-nav a:hover{color:#fff;border-bottom-color:#fff}

.foot-meta{
  flex:1 1 170px;
  min-width:150px;
  display:flex;
  align-items:baseline;
  justify-content:space-between;
  gap:18px;
}

.copy{margin:0;font-size:14px;color:#a5a5a5}

.to-top{
  display:inline-flex;
  align-items:center;
  min-height:40px;
  font-size:15px;
  color:#fff;
  text-decoration:none;
  border-bottom:1px solid rgba(255,255,255,.35);
}

.to-top:hover{border-bottom-color:#fff}

/* ---------- 底部胶囊导航 ---------- */
.dock{
  position:fixed;
  left:50%;
  bottom:14px;
  transform:translateX(-50%);
  z-index:60;
  display:grid;
  grid-template-columns:1fr auto 1fr;
  align-items:center;
  gap:10px;
  width:min(1180px,calc(100% - 20px));
  padding:8px 12px;
  border-radius:999px;
  border:1px solid rgba(31,31,31,.12);
  background:rgba(255,255,255,.8);
  -webkit-backdrop-filter:blur(16px) saturate(150%);
  backdrop-filter:blur(16px) saturate(150%);
  box-shadow:0 14px 40px rgba(31,31,31,.18),0 2px 6px rgba(31,31,31,.08);
}

.dock-group{
  display:flex;
  align-items:center;
  gap:6px;
  min-width:0;
}

.dock-left{justify-self:end}
.dock-right{justify-self:start}

.dock-link{
  display:inline-flex;
  align-items:center;
  min-height:42px;
  padding:0 13px;
  border-radius:999px;
  border:1px solid transparent;
  font-size:15px;
  color:var(--ink-2);
  text-decoration:none;
  white-space:nowrap;
  transition:background .22s,color .22s,border-color .22s;
}

.dock-link:hover{
  background:var(--mist);
  border-color:rgba(31,31,31,.16);
  color:var(--ink);
}

.dock-brand{
  justify-self:center;
  display:inline-flex;
  align-items:center;
  min-height:42px;
  padding:0 18px;
  border-radius:999px;
  border:1px solid rgba(31,31,31,.1);
  background:var(--mist);
  font-size:17px;
  font-weight:600;
  letter-spacing:-.01em;
  color:var(--ink);
  text-decoration:none;
  white-space:nowrap;
  box-shadow:var(--el-1);
}

.dock-search{
  display:flex;
  align-items:center;
  gap:4px;
  margin-left:6px;
  padding:2px 3px 2px 12px;
  border-radius:999px;
  border:1px solid rgba(31,31,31,.14);
  background:var(--paper);
  box-shadow:var(--el-1);
}

.dock-search input{
  width:102px;
  min-height:44px;
  border:0;
  outline:0;
  background:transparent;
  font:inherit;
  font-size:15px;
  color:var(--ink);
  -webkit-appearance:none;
  appearance:none;
}

.dock-search input::placeholder{color:#9a9a9a}

.dock-search button{
  flex:0 0 auto;
  width:44px;
  height:44px;
  display:grid;
  place-items:center;
  border:0;
  border-radius:50%;
  background:var(--ink);
  color:#fff;
  cursor:pointer;
  transition:background .2s;
}

.dock-search button:hover{background:#000}

.off{display:none !important}

/* ---------- 动效 ---------- */
@keyframes rise{
  from{opacity:0;transform:translateY(12px)}
  to{opacity:1;transform:none}
}

.js .reveal{
  opacity:0;
  transform:translateY(20px);
  transition:opacity .62s cubic-bezier(.2,.7,.3,1),transform .62s cubic-bezier(.2,.7,.3,1);
}

.js .reveal.in{opacity:1;transform:none}

.js .rail-list li,
.js .foot-nav dd,
.js .foot-nav dt{
  animation:rise .5s cubic-bezier(.2,.7,.3,1) both;
}

.js .rail-list li:nth-child(1),.js .foot-nav dd:nth-child(1){animation-delay:.03s}
.js .rail-list li:nth-child(2),.js .foot-nav dd:nth-child(2){animation-delay:.06s}
.js .rail-list li:nth-child(3),.js .foot-nav dd:nth-child(3){animation-delay:.09s}
.js .rail-list li:nth-child(4),.js .foot-nav dd:nth-child(4){animation-delay:.12s}
.js .rail-list li:nth-child(5),.js .foot-nav dd:nth-child(5){animation-delay:.15s}
.js .rail-list li:nth-child(6),.js .foot-nav dd:nth-child(6){animation-delay:.18s}
.js .rail-list li:nth-child(7),.js .foot-nav dd:nth-child(7){animation-delay:.21s}
.js .rail-list li:nth-child(8),.js .foot-nav dd:nth-child(8){animation-delay:.24s}

/* ---------- 断点 ---------- */
@media (max-width:960px){
  :root{--dock-h:64px}

  .hero{
    grid-template-columns:minmax(0,1fr);
    min-height:auto;
    gap:clamp(26px,6vw,44px);
    padding:42px clamp(16px,5vw,48px) clamp(40px,8vw,64px);
  }

  .hero-copy{
    order:-1;
    max-width:none;
    margin:0;
    text-align:left;
  }

  .lede{margin-left:0}
  .cta{justify-content:flex-start}
  .hero-stack{max-width:none;aspect-ratio:16/11;order:2}

  .stage{grid-template-columns:minmax(0,1fr)}
  .rail{position:static}

  .site-foot{flex-direction:column;gap:30px}
  .foot-brand,.foot-nav,.foot-meta{flex:0 0 auto;width:100%}

  .dock{
    display:flex;
    gap:6px;
    overflow-x:auto;
    overflow-y:hidden;
    padding:8px 10px;
    border-radius:24px;
    scrollbar-width:none;
    -webkit-overflow-scrolling:touch;
  }

  .dock::-webkit-scrollbar{display:none}
  .dock-group{display:contents}
  .dock-link,.dock-brand,.dock-search{flex:0 0 auto}
  .dock-brand{order:-1}
  .dock-search{margin-left:2px;order:99}
}

@media (max-width:520px){
  body{font-size:16px}
  .hero-copy h1{font-size:clamp(28px,8.4vw,34px)}
  .kicker{letter-spacing:.18em}
  .foot-nav dl{gap:6px 12px}
  .dock-link{min-height:44px}
  .dock-search input{width:76px}
  .prose{padding:18px 16px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .js .reveal{opacity:1;transform:none;transition:none}
  .js .rail-list li,.js .foot-nav dd,.js .foot-nav dt{animation:none}
  .pill,.foot-mark a,.dock-search button{transition:none}
}

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