@import url('https://fonts.googleapis.com/css2?family=Calistoga:ital@0;1&family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root{
  --ink:#1B1A2F;
  --ink-2:#252341;
  --ink-3:#33305a;
  --flame:#FF6B3D;
  --flame-d:#C93F0C;
  --paper:#F6F1E7;
  --paper-2:#EAE2D2;
  --muted:rgba(246,241,231,.66);
  --line:rgba(246,241,231,.14);
  --f-head:Calistoga,"Songti SC",Georgia,serif;
  --f-body:Inter,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --f-mono:"JetBrains Mono",ui-monospace,Menlo,monospace;
  --shadow:0 22px 48px -30px rgba(0,0,0,.95);
  --r:4px;
}

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

html{
  background:var(--ink);
  scroll-behavior:smooth;
  -webkit-text-size-adjust:100%;
}

body{
  margin:0;
  min-height:100vh;
  font-family:var(--f-body);
  font-size:17px;
  line-height:1.7;
  color:var(--paper);
  background-color:var(--ink);
  background-image:
    radial-gradient(1000px 620px at 12% -12%, rgba(255,107,61,.17), transparent 62%),
    radial-gradient(820px 700px at 105% 4%, rgba(122,108,232,.22), transparent 66%),
    radial-gradient(760px 700px at 50% 118%, rgba(255,107,61,.10), transparent 70%);
  background-attachment:fixed;
  overflow-x:clip;
  padding-bottom:calc(74px + env(safe-area-inset-bottom));
}

a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
h1,h2,h3,h4{line-height:1.2;margin:0}
p{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
button{font-family:inherit}

/* 顶部细条 */
.topper{
  position:relative;
  z-index:30;
  height:36px;
  display:flex;
  align-items:center;
  overflow:hidden;
  border-bottom:1px solid var(--line);
  background:rgba(20,19,38,.72);
  font-family:var(--f-mono);
  font-size:16px;
  letter-spacing:.05em;
  color:rgba(246,241,231,.55);
}
.topper-track{
  display:flex;
  gap:2.4em;
  white-space:nowrap;
  padding-left:20px;
  will-change:transform;
  animation:slide 36s linear infinite;
}
@keyframes slide{
  from{transform:translate3d(0,0,0)}
  to{transform:translate3d(-50%,0,0)}
}

/* 章节头部 */
.hero{
  position:relative;
  isolation:isolate;
  overflow:hidden;
  min-height:45vh;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  text-align:center;
  padding:clamp(30px,6vw,62px) 20px clamp(30px,5vw,52px);
  scroll-margin-top:16px;
}
.hero-layers{
  position:absolute;
  inset:-12% -10% -24%;
  z-index:-3;
  pointer-events:none;
}
.hero-layers .layer{
  position:absolute;
  display:block;
  border-radius:50%;
  filter:blur(64px);
  opacity:.5;
  will-change:transform;
}
.l1{width:62vw;height:62vw;left:-12vw;top:-14vw;background:rgba(255,107,61,.36)}
.l2{width:48vw;height:48vw;right:-10vw;top:8vw;background:rgba(124,110,230,.42)}
.l3{width:54vw;height:54vw;left:26vw;bottom:-24vw;background:rgba(255,107,61,.18)}

.hero-word{
  position:absolute;
  left:0;
  right:0;
  top:6%;
  z-index:-1;
  font-family:var(--f-head);
  font-size:clamp(74px,21vw,230px);
  line-height:.95;
  letter-spacing:-.02em;
  color:rgba(246,241,231,.07);
  text-align:center;
  pointer-events:none;
  will-change:transform;
}

.hero-copy{position:relative;z-index:2;max-width:820px}
.hero-copy::before{
  content:"";
  display:block;
  width:46px;
  height:3px;
  margin:0 auto 18px;
  background:var(--flame);
  border-radius:2px;
}
.hero h1{
  font-family:var(--f-head);
  font-size:clamp(30px,6.1vw,58px);
  letter-spacing:-.01em;
  color:var(--paper);
  text-wrap:balance;
}
.hero-desc{
  margin:14px auto 0;
  max-width:640px;
  font-size:17px;
  color:var(--muted);
}
.hero-media{
  position:relative;
  z-index:2;
  width:100%;
  max-width:960px;
  margin-top:clamp(20px,4vw,34px);
}
img.hero-img{
  width:100%;
  height:clamp(160px,26vh,300px);
  object-fit:cover;
  border-radius:var(--r);
  box-shadow:var(--shadow);
}

/* 主体 */
main{display:block}
section{
  display:grid;
  grid-template-columns:190px minmax(0,1fr);
  column-gap:clamp(20px,4vw,48px);
  row-gap:26px;
  max-width:1140px;
  margin:0 auto;
  padding:clamp(24px,5vw,58px) 20px clamp(30px,6vw,64px);
}
section > aside{
  grid-column:1;
  grid-row:1 / span 60;
}
section > div{
  grid-column:2;
  background:var(--paper);
  color:var(--ink);
  border-radius:var(--r);
  padding:clamp(22px,3.4vw,38px);
  box-shadow:var(--shadow);
  scroll-margin-top:78px;
}

section > div > *:first-child{margin-top:0}
section > div h2{
  font-family:var(--f-head);
  font-size:clamp(23px,3vw,33px);
  letter-spacing:-.01em;
  color:var(--ink);
  margin:0 0 10px;
}
section > div h3{font-size:20px;color:var(--ink);margin:26px 0 8px}
section > div hr{
  height:3px;
  width:54px;
  border:0;
  border-radius:2px;
  background:var(--flame);
  margin:0 0 20px;
}
section > div p{margin:0 0 16px}
section > div ul,section > div ol{margin:0 0 18px;padding-left:1.3em;list-style:disc}
section > div ol{list-style:decimal}
section > div li{margin:6px 0}
section > div a{color:var(--flame-d);text-decoration:underline;text-underline-offset:3px}
section > div strong{color:var(--ink);font-weight:700}
section > div blockquote{
  margin:0 0 18px;
  padding:12px 18px;
  border-left:3px solid var(--flame);
  background:var(--paper-2);
  border-radius:0 var(--r) var(--r) 0;
}
section > div table{
  display:block;
  width:100%;
  overflow-x:auto;
  border-collapse:collapse;
  font-size:16px;
  margin-bottom:18px;
}
section > div th,section > div td{
  border:1px solid rgba(27,26,47,.2);
  padding:9px 12px;
  text-align:left;
}
section > div img{border-radius:var(--r);margin:6px 0 18px}
section > div code{
  font-family:var(--f-mono);
  font-size:.95em;
  background:var(--paper-2);
  padding:1px 5px;
  border-radius:3px;
}

/* 侧栏 */
.rail{
  position:sticky;
  top:22px;
  align-self:start;
  padding:6px 0;
  scroll-margin-top:78px;
}
.rail-h{
  font-family:var(--f-body);
  font-size:16px;
  font-weight:600;
  letter-spacing:.22em;
  color:var(--paper);
  opacity:.6;
}
.rail hr{
  height:2px;
  width:34px;
  border:0;
  background:var(--flame);
  margin:10px 0 14px;
}
.rail-list{display:flex;flex-direction:column}
.rail-list a{
  display:flex;
  align-items:center;
  min-height:40px;
  padding:2px 0;
  font-size:16px;
  color:var(--muted);
  border-bottom:1px dashed rgba(246,241,231,.12);
  transition:color .2s ease, padding-left .2s ease;
}
.rail-list a:hover{color:var(--flame);padding-left:5px}

/* 页脚 */
.foot{
  display:grid;
  grid-template-columns:1.5fr 1fr auto;
  gap:clamp(20px,4vw,48px);
  align-items:start;
  padding:clamp(36px,7vw,76px) clamp(20px,5vw,54px) calc(28px + env(safe-area-inset-bottom));
  border-top:1px solid var(--line);
  background:linear-gradient(180deg, rgba(37,35,65,.55), rgba(20,19,38,.98));
  scroll-margin-top:16px;
}
.foot-brand{
  font-family:var(--f-head);
  font-size:clamp(46px,11vw,132px);
  line-height:.92;
  letter-spacing:-.02em;
  color:var(--paper);
}
.foot-desc{margin-top:14px;max-width:36ch;font-size:16px;color:var(--muted)}
.foot-list{display:flex;flex-wrap:wrap;gap:0 18px}
.foot-list a{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  font-size:16px;
  color:var(--muted);
  transition:color .2s ease;
}
.foot-list a:hover{color:var(--flame)}
.totop{
  min-height:44px;
  padding:0 16px;
  background:transparent;
  color:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--r);
  font-size:16px;
  cursor:pointer;
  transition:background .2s ease,color .2s ease,border-color .2s ease;
}
.totop:hover{background:var(--flame);color:var(--ink);border-color:var(--flame)}
.copy{margin-top:12px;font-size:16px;color:rgba(246,241,231,.5)}

/* 底部固定条 */
.dock{
  position:fixed;
  left:0;
  right:0;
  bottom:0;
  z-index:60;
  display:flex;
  align-items:center;
  gap:8px;
  padding:8px clamp(12px,3vw,26px) calc(8px + env(safe-area-inset-bottom));
  background:rgba(19,18,36,.95);
  backdrop-filter:blur(12px);
  border-top:1px solid var(--line);
}
.dock-brand{
  display:flex;
  align-items:center;
  gap:9px;
  min-height:44px;
  padding:0 10px;
  font-family:var(--f-head);
  font-size:20px;
  color:var(--paper);
}
.dock-logo{width:30px;height:30px;border-radius:50%;object-fit:cover}
.dock-ol{
  display:flex;
  align-items:center;
  gap:2px;
  margin-left:auto;
  list-style:none;
}
.dock-ol a,.dock-sum{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:0 12px;
  font-size:16px;
  color:rgba(246,241,231,.8);
  border-radius:var(--r);
  transition:background .2s ease,color .2s ease;
}
.dock-ol a:hover{color:var(--paper);background:rgba(255,107,61,.16)}
.dock-grp{position:relative}
.dock-sum{
  cursor:pointer;
  list-style:none;
  color:var(--flame);
  border:1px solid rgba(255,107,61,.4);
}
.dock-sum::-webkit-details-marker{display:none}
.dock-grp details:not([open]) .dock-sub{display:none}
.dock-sub{
  position:absolute;
  bottom:calc(100% + 10px);
  left:50%;
  transform:translateX(-50%);
  display:flex;
  flex-direction:column;
  gap:2px;
  min-width:186px;
  padding:8px;
  background:var(--ink-2);
  border:1px solid var(--line);
  border-radius:6px;
  box-shadow:0 24px 44px -22px #000;
}
.dock-sub a{width:100%}
.dock-btn{
  display:none;
  align-items:center;
  min-height:44px;
  padding:0 15px;
  margin-left:auto;
  border:0;
  border-radius:var(--r);
  background:var(--flame);
  color:var(--ink);
  font-size:16px;
  font-weight:600;
  cursor:pointer;
}

/* 滚动浮现 */
.js section > div,
.js .foot > div,
.js .rail{
  opacity:0;
  transform:translateY(24px);
  transition:opacity .7s cubic-bezier(.2,.7,.3,1), transform .7s cubic-bezier(.2,.7,.3,1);
}
.js section > div:nth-child(3){transition-delay:.06s}
.js section > div:nth-child(4){transition-delay:.1s}
.js .is-in{opacity:1;transform:none}

@media (max-width:900px){
  section{
    grid-template-columns:minmax(0,1fr);
    row-gap:20px;
    padding-top:26px;
  }
  section > aside{
    grid-column:1;
    grid-row:auto;
    position:static;
    padding:0;
  }
  .rail hr{margin:8px 0 10px}
  .rail-list{
    flex-direction:row;
    gap:8px;
    overflow-x:auto;
    padding-bottom:6px;
  }
  .rail-list a{
    min-height:40px;
    padding:0 12px;
    white-space:nowrap;
    border:1px solid var(--line);
    border-radius:999px;
    color:var(--paper);
    background:rgba(246,241,231,.05);
  }
  .rail-list a:hover{padding-left:12px;color:var(--flame);border-color:var(--flame)}
  .foot{grid-template-columns:minmax(0,1fr);gap:24px}
  .foot-c{display:flex;align-items:center;gap:16px;flex-wrap:wrap}
  .copy{margin-top:0}
}

@media (max-width:820px){
  .dock{flex-wrap:wrap;padding-top:6px}
  .dock-btn{display:flex}
  .dock-ol{
    order:5;
    width:100%;
    flex-direction:column;
    align-items:stretch;
    gap:0;
    margin-left:0;
    max-height:62vh;
    overflow-y:auto;
    display:none;
  }
  .dock[data-open] .dock-ol{display:flex}
  .dock-ol a,.dock-sum{
    min-height:48px;
    padding:0 6px;
    border-bottom:1px solid rgba(246,241,231,.1);
    border-radius:0;
  }
  .dock-sum{border:0;border-bottom:1px solid rgba(246,241,231,.1);justify-content:space-between}
  .dock-sum::after{content:"+";color:var(--paper);opacity:.6}
  .dock-grp details[open] .dock-sum::after{content:"–"}
  .dock-sub{
    position:static;
    transform:none;
    min-width:0;
    border:0;
    box-shadow:none;
    background:transparent;
    padding:0 0 6px 14px;
  }
}

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  .topper-track{animation:none}
  .js section > div,
  .js .foot > div,
  .js .rail{opacity:1;transform:none;transition:none}
  .rail-list a{transition:none}
}

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