@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:ital,wght@0,400;0,500;0,700;1,400&display=swap');

:root{
  --ink:#0a0a0a;
  --bg:#ffffff;
  --soft:#f3f3f3;
  --line:#e7e7e7;
  --muted:#6b6b6b;
  --r:28px;
}

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

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

body{
  margin:0;
  padding-bottom:122px;
  background:var(--bg);
  color:var(--ink);
  font-family:'Plus Jakarta Sans',system-ui,-apple-system,'PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  font-size:16px;
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
}

img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
ul,ol,dl{margin:0}
:focus-visible{outline:2px solid #000;outline-offset:3px;border-radius:6px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}

/* ---------- 角落品牌 ---------- */
.brandbar{
  position:fixed;
  inset:0 0 auto 0;
  height:72px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:0 clamp(1rem,4vw,2.5rem);
  z-index:60;
  background:linear-gradient(#fff 58%,rgba(255,255,255,.82));
  backdrop-filter:blur(10px);
}
.mark{
  width:44px;height:44px;
  display:grid;place-items:center;
  border-radius:16px;
  background:#000;color:#fff;
  font-weight:700;font-size:1.05rem;
  overflow:hidden;flex:none;
  transition:transform .22s ease;
}
.mark:hover{transform:translateY(-2px)}
.mark img{width:100%;height:100%;object-fit:cover;border-radius:0}
.mark.sm{width:38px;height:38px;border-radius:13px;font-size:.95rem}
.contact{
  display:inline-flex;align-items:center;
  min-height:44px;padding:0 1.15rem;
  border:1px solid var(--line);border-radius:24px;
  font-size:.9rem;
  transition:background .22s ease,color .22s ease,border-color .22s ease;
}
.contact:hover{background:#000;color:#fff;border-color:#000}

/* ---------- 首屏 ---------- */
.hero{
  position:relative;
  min-height:100vh;
  display:grid;
  align-content:center;
  overflow:hidden;
  padding:7rem clamp(1rem,4vw,2.5rem) 4.5rem;
}
.hero-mark{
  position:absolute;
  right:-.05em;top:50%;
  transform:translateY(-50%);
  font-size:clamp(9rem,30vw,23rem);
  font-weight:700;
  letter-spacing:-.07em;
  line-height:.76;
  color:#f1f1f1;
  pointer-events:none;
  user-select:none;
  z-index:0;
}
.hero-inner{
  position:relative;
  z-index:1;
  width:100%;
  max-width:1200px;
  margin:0 auto;
  display:grid;
  grid-template-columns:1.05fr .95fr;
  gap:clamp(1.5rem,5vw,4rem);
  align-items:center;
}
.kicker{
  margin:0 0 .9rem;
  font-size:.76rem;
  letter-spacing:.3em;
  font-weight:500;
  color:var(--muted);
}
.hero h1{
  margin:0;
  max-width:16ch;
  font-size:clamp(2.1rem,5.8vw,4.3rem);
  line-height:1.04;
  letter-spacing:-.035em;
  font-weight:700;
}
.lede{
  margin:1.4rem 0 0;
  max-width:36ch;
  font-size:clamp(1rem,1.5vw,1.12rem);
  line-height:1.72;
  color:#3c3c3c;
}
.hero-act{margin:2rem 0 0}
.btn{
  display:inline-flex;align-items:center;justify-content:center;
  min-height:50px;padding:0 2rem;
  border-radius:26px;
  background:#000;color:#fff;
  font-size:.95rem;font-weight:500;
  transition:transform .22s ease,opacity .22s ease;
}
.btn:hover{opacity:.85;transform:translateY(-2px)}
.hero-fig{
  margin:0;
  aspect-ratio:4/5;
  border-radius:var(--r);
  overflow:hidden;
  background:var(--soft);
  box-shadow:0 34px 66px -36px rgba(0,0,0,.42);
}
.hero-fig img{width:100%;height:100%;object-fit:cover}

/* ---------- 主体网格 ---------- */
.wrap{
  max-width:1200px;
  margin:0 auto;
  padding:2rem clamp(1rem,4vw,2.5rem) 3rem;
  display:grid;
  grid-template-columns:220px minmax(0,1fr);
  gap:clamp(1.5rem,4vw,3.5rem);
  align-items:start;
}
.rail{
  position:sticky;
  top:96px;
  padding:1.4rem 1.15rem;
  border:1px solid var(--line);
  border-radius:var(--r);
  background:#fff;
  box-shadow:0 22px 46px -34px rgba(0,0,0,.55);
}
.rail small{
  display:block;
  margin-bottom:.35rem;
  font-size:.66rem;
  letter-spacing:.26em;
  color:var(--muted);
}
.rail-h{
  margin:0 0 .9rem;
  font-size:1.05rem;
  letter-spacing:-.01em;
}
.rail-list{list-style:none;padding:0;display:grid;gap:.12rem}
.rail-list a{
  display:flex;align-items:center;
  min-height:40px;padding:0 .6rem;
  border-radius:14px;
  font-size:.9rem;color:#2b2b2b;
  transition:background .2s ease,color .2s ease;
}
.rail-list a:hover{background:#000;color:#fff}
.col{min-width:0}

/* ---------- 正文 ---------- */
.prose{
  max-width:44rem;
  font-size:1.0625rem;
  line-height:1.78;
  color:#141414;
}
.prose [id]{scroll-margin-top:104px}
.prose article + article{
  margin-top:3.5rem;
  padding-top:3.5rem;
  border-top:1px solid #ededed;
}
.prose small{
  display:block;
  margin-bottom:.55rem;
  font-size:.7rem;
  line-height:1.4;
  letter-spacing:.24em;
  color:#8c8c8c;
}
.prose h2{
  margin:0 0 1.1rem;
  font-size:clamp(1.45rem,2.9vw,2.05rem);
  line-height:1.22;
  letter-spacing:-.025em;
  font-weight:700;
}
.prose h3{
  margin:2rem 0 .75rem;
  font-size:clamp(1.12rem,1.9vw,1.35rem);
  line-height:1.32;
  letter-spacing:-.015em;
}
.prose p{margin:0 0 1.15rem}
.prose ul,.prose ol{margin:0 0 1.3rem;padding-left:1.3rem}
.prose li{margin:0 0 .5rem}
.prose li::marker{color:#000}
.prose a{
  text-decoration:underline;
  text-decoration-thickness:1px;
  text-underline-offset:3px;
  transition:background .2s ease;
}
.prose a:hover{background:#efefef}
.prose blockquote{
  margin:1.6rem 0;
  padding:.15rem 0 .15rem 1.2rem;
  border-left:2px solid #000;
  color:#343434;
}
.prose img{margin:1.5rem 0;border-radius:20px;height:auto}
.prose strong{font-weight:700}
.prose hr{border:0;border-top:1px solid #eee;margin:2.5rem 0}

/* ---------- 底部导航条 ---------- */
.dock{
  position:fixed;
  left:50%;bottom:14px;
  transform:translateX(-50%);
  z-index:70;
  display:flex;align-items:center;gap:.28rem;
  max-width:calc(100vw - 1.5rem);
  padding:.35rem;
  border:1px solid var(--line);
  border-radius:var(--r);
  background:rgba(255,255,255,.94);
  box-shadow:0 24px 48px -24px rgba(0,0,0,.48);
  backdrop-filter:blur(10px);
}
.grp{position:relative}
.dock summary{
  list-style:none;
  cursor:pointer;
  display:flex;align-items:center;
  min-height:44px;padding:0 1.1rem;
  border-radius:22px;
  font-size:.9rem;font-weight:500;
  white-space:nowrap;
  transition:background .2s ease,color .2s ease;
}
.dock summary::-webkit-details-marker{display:none}
.dock summary::marker{content:''}
.dock summary:hover{background:var(--soft)}
.grp[open] summary{background:#000;color:#fff}
.panel{
  position:absolute;
  bottom:calc(100% + .6rem);
  left:0;
  min-width:11rem;
  display:grid;gap:.1rem;
  padding:.4rem;
  border:1px solid var(--line);
  border-radius:22px;
  background:#fff;
  box-shadow:0 26px 52px -26px rgba(0,0,0,.48);
}
.grp:nth-of-type(2) .panel{left:auto;right:0}
.panel a{
  display:flex;align-items:center;
  min-height:44px;padding:0 .9rem;
  border-radius:16px;
  font-size:.9rem;white-space:nowrap;
  transition:background .2s ease;
}
.panel a:hover{background:var(--soft)}
.up{
  display:flex;align-items:center;
  min-height:44px;padding:0 1.05rem;
  border-radius:22px;
  background:#000;color:#fff;
  font-size:.88rem;white-space:nowrap;
  transition:opacity .2s ease;
}
.up:hover{opacity:.85}

/* ---------- 页脚 ---------- */
.foot{
  max-width:1200px;
  margin:1rem auto 0;
  padding:2.5rem clamp(1rem,4vw,2.5rem) 6rem;
  display:flex;flex-wrap:wrap;
  align-items:flex-start;justify-content:space-between;
  gap:1.5rem 2rem;
  border-top:1px solid var(--line);
}
.foot-brand{
  display:flex;align-items:center;gap:.6rem;
  font-weight:700;letter-spacing:-.01em;
}
.foot-nav{flex:1 1 17rem;min-width:0}
.foot-nav dl{
  display:flex;flex-wrap:wrap;
  align-items:center;gap:.1rem .25rem;
}
.foot-nav dt{
  display:flex;align-items:center;
  min-height:40px;
  margin-right:.35rem;
  font-size:.66rem;letter-spacing:.22em;
  color:var(--muted);
}
.foot-nav dd{margin:0}
.foot-nav dd a{
  display:inline-flex;align-items:center;
  min-height:40px;padding:0 .55rem;
  border-radius:12px;
  font-size:.88rem;color:#2b2b2b;
  transition:background .2s ease;
}
.foot-nav dd a:hover{background:var(--soft)}
.foot-end{
  display:grid;justify-items:center;gap:.6rem;
  margin-left:auto;
  text-align:center;
}
.sub{
  display:flex;align-items:center;gap:.35rem;
  padding:.2rem .2rem .2rem 1rem;
  border:1px solid var(--line);
  border-radius:24px;
  background:#fff;
}
.sub input{
  width:8rem;min-height:40px;
  border:0;background:transparent;outline:none;
  font:inherit;font-size:.88rem;color:var(--ink);
}
.sub button{
  min-height:40px;padding:0 1rem;
  border:0;border-radius:22px;
  background:#000;color:#fff;
  font:inherit;font-size:.85rem;
  cursor:pointer;
  transition:opacity .2s ease;
}
.sub button:hover{opacity:.85}
.copy{margin:0;font-size:.76rem;color:var(--muted)}

/* ---------- 动效 ---------- */
@keyframes rise{
  from{opacity:0;transform:translateY(14px)}
  to{opacity:1;transform:none}
}
.hero-copy > *{animation:rise .6s cubic-bezier(.2,.7,.2,1) both}
.hero-copy > *:nth-child(2){animation-delay:.07s}
.hero-copy > *:nth-child(3){animation-delay:.14s}
.hero-copy > *:nth-child(4){animation-delay:.21s}

/* ---------- 断点 ---------- */
@media (max-width:900px){
  .hero-inner{grid-template-columns:1fr}
  .hero-fig{aspect-ratio:3/2}
  .wrap{grid-template-columns:1fr;padding-top:1rem}
  .rail{position:static}
  .rail-list{display:flex;flex-wrap:wrap;gap:.2rem}
  .rail-list a{padding:0 .7rem}
  .foot-end{margin-left:0}
}

@media (max-width:600px){
  .hero{min-height:auto;padding-top:6rem;padding-bottom:3rem}
  .hero-mark{font-size:36vw;opacity:.95}
  .lede{max-width:none}
  .dock summary{padding:0 .85rem;font-size:.85rem}
  .up{padding:0 .8rem;font-size:.82rem}
  .prose{font-size:1rem}
  .foot{padding-bottom:7rem}
  .foot-end{width:100%}
}

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

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