:root{
  --ink:#1c1726;
  --ink2:#120d1a;
  --p1:#6514ff;
  --p2:#bf00ff;
  --fg:#f5f1ff;
  --dim:rgba(245,241,255,.74);
  --line:rgba(245,241,255,.18);
  --card:rgba(28,23,38,.74);
  --r:4px;
  --gap:48px;
  --rail:236px;
}

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

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

body{
  margin:0;
  background-color:var(--ink2);
  color:var(--fg);
  font-family:'Atkinson Hyperlegible',system-ui,-apple-system,"Segoe UI","Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  font-size:17px;
  line-height:1.7;
  letter-spacing:.01em;
  overflow-x:hidden;
}

body::before{
  content:"";
  position:fixed;
  inset:-25% -25%;
  z-index:0;
  pointer-events:none;
  background-image:
    radial-gradient(closest-side,rgba(101,20,255,.34),transparent 78%),
    radial-gradient(closest-side,rgba(191,0,255,.24),transparent 78%),
    repeating-linear-gradient(45deg,rgba(245,241,255,.05) 0 1px,transparent 1px 26px);
  background-size:62% 72%,56% 66%,auto;
  background-position:82% 4%,4% 96%,0 0;
  background-repeat:no-repeat,no-repeat,repeat;
  animation:pan 26s linear infinite alternate;
}

@keyframes pan{
  from{transform:translate3d(0,0,0)}
  to{transform:translate3d(-26px,20px,0)}
}

a{color:var(--fg);text-decoration:none}
a:hover{color:#fff}
img{display:block;max-width:100%;height:auto}
:focus-visible{outline:2px solid var(--p2);outline-offset:3px}

/* 左侧固定栏 */
.rail{
  position:fixed;
  left:0;
  top:0;
  bottom:0;
  z-index:30;
  width:var(--rail);
  display:flex;
  flex-direction:column;
  gap:22px;
  padding:26px 22px 24px;
  background:linear-gradient(180deg,rgba(28,23,38,.97),rgba(18,13,26,.99));
  border-right:2px solid var(--line);
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:10px;
  min-height:40px;
  font-size:18px;
  font-weight:700;
  line-height:1.25;
}

.bmark{
  flex:none;
  width:15px;
  height:15px;
  border-radius:2px;
  background:linear-gradient(135deg,var(--p1),var(--p2));
  transform:rotate(12deg);
}

.rail nav{margin-top:6px}
.rail nav p{
  margin:0;
  display:flex;
  flex-direction:column;
  gap:2px;
}

.rail nav a{
  display:flex;
  align-items:center;
  min-height:42px;
  padding:8px 10px;
  font-size:16px;
  color:var(--dim);
  border-left:2px solid transparent;
  border-radius:var(--r);
  transition:color .2s,background .2s,border-color .2s,transform .2s;
}

.rail nav a:hover{
  color:#fff;
  background:rgba(101,20,255,.24);
  border-left-color:var(--p2);
  transform:translateX(3px);
}

.rail nav a.is-on{
  color:#fff;
  background:rgba(191,0,255,.16);
  border-left-color:var(--p2);
}

.cta{
  margin-top:auto;
  display:flex;
  align-items:center;
  justify-content:center;
  min-height:46px;
  padding:12px 16px;
  font-size:16px;
  font-weight:700;
  text-align:center;
  color:#fff;
  background:linear-gradient(120deg,var(--p1),var(--p2));
  border-radius:var(--r);
  transition:filter .2s,transform .2s;
}

.cta:hover{filter:brightness(1.14);transform:translateY(-2px)}

/* 主体 */
main{
  position:relative;
  z-index:1;
  margin-left:var(--rail);
}

.hero{
  position:relative;
  overflow:hidden;
  display:grid;
  grid-template-columns:minmax(0,.85fr) minmax(0,1.15fr);
  gap:var(--gap);
  align-items:center;
  min-height:70vh;
  padding:56px var(--gap) 64px;
  border-bottom:2px solid var(--line);
}

.hero-bg{
  position:absolute;
  left:-10px;
  bottom:-.16em;
  z-index:0;
  font-size:clamp(72px,15vw,220px);
  font-weight:700;
  line-height:.8;
  letter-spacing:-.02em;
  color:transparent;
  -webkit-text-stroke:2px rgba(191,0,255,.32);
  white-space:nowrap;
  pointer-events:none;
}

.hero-fig{
  position:relative;
  z-index:1;
  margin:0;
  aspect-ratio:4/3;
  overflow:hidden;
  border:2px solid var(--p1);
  border-radius:var(--r);
  background:linear-gradient(140deg,rgba(101,20,255,.5),rgba(191,0,255,.36));
}

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

.hero-fig::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background:linear-gradient(160deg,rgba(101,20,255,.42),rgba(191,0,255,.34));
  mix-blend-mode:screen;
}

.fig-mark{
  display:block;
  width:100%;
  height:100%;
  background-image:repeating-linear-gradient(135deg,rgba(245,241,255,.38) 0 3px,transparent 3px 16px);
}

.hero-copy{
  position:relative;
  z-index:1;
  text-align:center;
}

h1{
  margin:0 0 18px;
  font-size:clamp(32px,4.4vw,60px);
  line-height:1.06;
  letter-spacing:-.015em;
}

.lead{
  margin:0 auto;
  max-width:32ch;
  font-size:clamp(16px,1.4vw,19px);
  color:var(--dim);
}

/* 侧栏 + 正文 */
.shell{
  display:grid;
  grid-template-columns:216px minmax(0,1fr);
  gap:var(--gap);
  align-items:start;
  padding:64px var(--gap) 88px;
}

.toc{
  position:sticky;
  top:32px;
  padding:16px;
  border:2px solid var(--line);
  border-radius:var(--r);
  background:var(--card);
}

.toc-h{
  margin:0 0 10px;
  font-size:16px;
  letter-spacing:.06em;
}

.toc-h span{display:inline-flex;align-items:center;gap:8px}
.toc-h span::before{
  content:"";
  width:10px;
  height:10px;
  border-radius:2px;
  background:var(--p2);
  transform:rotate(45deg);
}

.toc-links{
  margin:0;
  display:flex;
  flex-direction:column;
}

.toc-links a{
  display:flex;
  align-items:center;
  min-height:40px;
  padding:7px 0;
  font-size:16px;
  color:var(--dim);
  border-bottom:1px dashed rgba(245,241,255,.14);
  transition:color .2s,padding .2s;
}

.toc-links a:last-child{border-bottom:0}
.toc-links a:hover{color:#fff;padding-left:5px}

.body-col{min-width:0}

.body-h{
  margin:0 0 30px;
  font-size:clamp(22px,2.4vw,28px);
  letter-spacing:.02em;
}

.body-h span{
  display:inline-block;
  padding-bottom:4px;
  border-bottom:3px solid var(--p2);
  color:var(--p2);
}

.body-col > div{
  scroll-margin-top:96px;
  padding-block:6px;
}

.body-col > div + div{
  margin-top:var(--gap);
  padding-top:var(--gap);
  border-top:1px solid var(--line);
}

.body-col h2,
.body-col h3{
  margin:0 0 16px;
  font-size:clamp(22px,2.8vw,32px);
  line-height:1.22;
  letter-spacing:-.01em;
}

.body-col h2 span,
.body-col h3 span{
  background:linear-gradient(transparent 64%,rgba(191,0,255,.5) 64%);
}

.body-col p,
.body-col li{max-width:66ch}
.body-col p{margin:0 0 1.05em}
.body-col ul,
.body-col ol{padding-left:1.35em;margin:0 0 1.2em}
.body-col li{margin-bottom:.5em}
.body-col a{color:var(--p2);text-decoration:underline;text-underline-offset:3px}
.body-col a:hover{color:#fff}
.body-col figure{margin:26px 0}
.body-col figure img{border:2px solid var(--line);border-radius:var(--r)}
.body-col strong{color:#fff}
.body-col blockquote{
  margin:26px 0;
  padding:16px 20px;
  border-left:4px solid var(--p2);
  background:rgba(101,20,255,.14);
  border-radius:0 var(--r) var(--r) 0;
}
.body-col blockquote p:last-child{margin-bottom:0}
.body-col hr{border:0;border-top:1px solid var(--line);margin:32px 0}

/* 页脚 */
.foot{
  position:relative;
  z-index:1;
  margin-left:var(--rail);
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:30px var(--gap);
  padding:52px var(--gap) 48px;
  border-top:2px solid var(--line);
  background:rgba(28,23,38,.62);
}

.foot-brand{
  margin:0;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:10px;
  font-size:18px;
  font-weight:700;
}

.foot-desc{
  flex-basis:100%;
  font-size:16px;
  font-weight:400;
  line-height:1.65;
  color:var(--dim);
}

.foot-links{
  margin:0;
  display:flex;
  flex-wrap:wrap;
  gap:2px 18px;
  align-content:start;
}

.foot-links a{
  display:inline-flex;
  align-items:center;
  min-height:40px;
  font-size:16px;
  color:var(--dim);
}

.foot-links a:hover{color:#fff}

.foot-bar{
  grid-column:1/-1;
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  gap:10px 24px;
  padding-top:16px;
  font-size:16px;
  color:var(--dim);
  border-top:1px dashed var(--line);
}

.foot-bar a{display:inline-flex;align-items:center;min-height:40px}

/* 滚动显现 */
.rv{
  opacity:0;
  transform:translateY(16px);
  transition:opacity .45s ease,transform .45s ease;
}

.rv.in{opacity:1;transform:none}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  body::before{animation:none}
  .rv{opacity:1;transform:none;transition:none}
  *{transition-duration:.01ms!important;animation-duration:.01ms!important}
}

/* 移动端 */
@media (max-width:900px){
  body{font-size:16.5px}

  .rail{
    position:sticky;
    top:0;
    left:auto;
    right:auto;
    bottom:auto;
    width:auto;
    flex-direction:row;
    flex-wrap:wrap;
    align-items:center;
    gap:8px 12px;
    padding:10px 16px 0;
    border-right:0;
    border-bottom:2px solid var(--line);
    background:rgba(18,13,26,.96);
    backdrop-filter:blur(10px);
  }

  .brand{order:1;font-size:17px}

  .rail nav{
    order:3;
    width:100%;
    margin:0;
    overflow-x:auto;
    -webkit-overflow-scrolling:touch;
  }

  .rail nav p{flex-direction:row;gap:4px;padding-bottom:2px}

  .rail nav a{
    min-height:44px;
    padding:10px 8px;
    white-space:nowrap;
    border-left:0;
    border-bottom:2px solid transparent;
    border-radius:0;
  }

  .rail nav a:hover{transform:none;background:transparent;color:#fff}

  .rail nav a.is-on{
    background:transparent;
    border-left:0;
    border-bottom-color:var(--p2);
  }

  .cta{
    order:2;
    margin:0 0 0 auto;
    min-height:42px;
    padding:10px 14px;
    font-size:16px;
  }

  main,.foot{margin-left:0}

  .hero{
    grid-template-columns:1fr;
    gap:22px;
    min-height:0;
    padding:22px 18px 40px;
  }

  .hero-fig{aspect-ratio:16/7}

  .hero-bg{
    left:-6px;
    bottom:-.08em;
    font-size:clamp(54px,20vw,120px);
    opacity:.9;
  }

  .hero-copy h1{font-size:clamp(28px,7.4vw,40px);margin-bottom:12px}

  .shell{
    grid-template-columns:1fr;
    gap:26px;
    padding:30px 18px 60px;
  }

  .body-col{order:1}
  .toc{order:2;position:static}

  .toc-links{flex-direction:row;flex-wrap:wrap;gap:0 16px}
  .toc-links a{border-bottom:0;min-height:40px}

  .body-col > div{scroll-margin-top:126px}

  .body-col > div + div{
    margin-top:36px;
    padding-top:36px;
  }

  .foot{
    grid-template-columns:1fr;
    gap:20px;
    padding:34px 18px 40px;
  }
}

@media (max-width:420px){
  .brand .bname{max-width:52vw;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .hero{padding-top:18px}
}

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