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

:root{
  --ink:#1f1726;
  --ink-2:#4b4055;
  --purple:#56228b;
  --brown:#8b4513;
  --cream:#f6f1e8;
  --paper:#fffdf8;
  --sand:#ece1d1;
  --line:#dccfbb;
  --rail:238px;
  --r:18px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:var(--cream);
  color:var(--ink);
  font-family:'Fira Sans',system-ui,-apple-system,'Noto Sans SC','PingFang SC','Microsoft YaHei',sans-serif;
  font-size:17px;
  line-height:1.75;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
body::before{
  content:"";
  position:fixed;
  inset:-20% -10% auto -10%;
  height:130vh;
  z-index:-1;
  pointer-events:none;
  background:
    radial-gradient(36vw 36vw at 6% 3%, rgba(86,34,139,.11), transparent 62%),
    radial-gradient(28vw 28vw at 94% 16%, rgba(139,69,19,.11), transparent 60%),
    radial-gradient(26vw 26vw at 68% 88%, rgba(86,34,139,.07), transparent 64%);
}

img{max-width:100%;height:auto;display:block}
a{color:var(--purple);text-underline-offset:3px;text-decoration-thickness:1px}
a:focus-visible,input:focus-visible{outline:2px solid var(--purple);outline-offset:2px}

/* 左侧固定竖排导航 */
.rail{
  position:fixed;
  inset:0 auto 0 0;
  width:var(--rail);
  z-index:30;
  display:flex;
  flex-direction:column;
  gap:1rem;
  padding:1.3rem .95rem 1.6rem;
  background:rgba(255,253,248,.94);
  border-right:1px solid var(--line);
  overflow-y:auto;
}
.brand{
  display:flex;
  align-items:center;
  gap:.6rem;
  min-height:48px;
  text-decoration:none;
  color:var(--ink);
}
.mark{
  flex:0 0 auto;
  width:38px;
  height:38px;
  display:grid;
  place-items:center;
  overflow:hidden;
  border-radius:12px 20px 12px 22px;
  background:var(--purple);
  color:#fffaf2;
  border:1px solid #3f1869;
  font-family:'Fira Code',monospace;
  font-weight:700;
  font-size:1.1rem;
}
.mark img{width:100%;height:100%;object-fit:cover}
.mark svg{width:70%;height:70%}
.brand-name{
  font-family:'Fira Code',monospace;
  font-weight:700;
  font-size:1.06rem;
  letter-spacing:.03em;
  line-height:1.3;
}
.rail-nav ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:2px}
.rail-nav a{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:.4rem .7rem;
  border:1px solid transparent;
  border-radius:12px 18px 12px 18px;
  color:var(--ink-2);
  font-size:1rem;
  line-height:1.4;
  text-decoration:none;
  transition:background .18s ease,color .18s ease,border-color .18s ease,transform .18s ease;
}
.rail-nav a:hover{
  background:var(--paper);
  color:var(--purple);
  border-color:var(--line);
  transform:translateX(3px);
}
.search input{
  width:100%;
  min-height:44px;
  padding:.5rem .85rem;
  font:inherit;
  font-size:1rem;
  color:var(--ink);
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:999px;
}
.search input::placeholder{color:#8a7f92}

/* 主区 */
.stage{
  margin-left:var(--rail);
  padding:clamp(1rem,3vw,2.4rem) clamp(1rem,3vw,2rem) 3rem;
  display:grid;
  grid-template-columns:minmax(0,1fr) 250px;
  gap:clamp(1rem,2.4vw,2rem);
  align-items:start;
}
main,article{min-width:0}

/* Hero：双图错位 + 右对齐文案 + 满屏 */
.hero{
  min-height:100vh;
  display:grid;
  grid-template-columns:1.05fr .95fr;
  gap:clamp(1rem,3vw,2.4rem);
  align-items:center;
  padding:clamp(1rem,3vw,2rem) 0 clamp(2rem,5vw,3.4rem);
}
.hero-media{
  position:relative;
  min-height:clamp(240px,52vh,520px);
}
.tile{
  position:absolute;
  overflow:hidden;
  border:1px solid var(--line);
  background:linear-gradient(150deg,#e6d9ec,#d9e8dd 58%,#f0e2cf);
}
.tile-a{
  inset:0 16% 20% 0;
  border-radius:58% 42% 46% 54%/52% 46% 54% 48%;
}
.tile-b{
  width:47%;
  aspect-ratio:1;
  right:0;
  bottom:0;
  border-radius:48% 52% 55% 45%/45% 55% 45% 55%;
  box-shadow:0 20px 34px -26px rgba(31,23,38,.6);
}
.tile-img{width:100%;height:100%;object-fit:cover}
.badge{
  position:absolute;
  left:0;
  top:4%;
  z-index:3;
  margin:0;
  transform:rotate(-3deg);
  background:var(--brown);
  color:#fff6ea;
  font-family:'Fira Code',monospace;
  font-size:.95rem;
  letter-spacing:.08em;
  padding:.35rem .85rem;
  border-radius:999px;
  border:1px solid #6d360f;
}
.hero-copy{text-align:right}
.hero h1{
  font-family:'Fira Code',monospace;
  font-size:clamp(1.9rem,4.4vw,3.1rem);
  line-height:1.22;
  letter-spacing:-.02em;
  margin:0 0 .9rem;
}
.lede{
  margin:0 0 0 auto;
  max-width:38ch;
  text-align:right;
  color:var(--ink-2);
  font-size:1rem;
}

/* 正文卡片 */
main article > section:not(.hero){
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--r);
  padding:clamp(1.1rem,2.6vw,2rem);
  margin-bottom:1.15rem;
  scroll-margin-top:26px;
}
main h2{
  font-family:'Fira Code',monospace;
  font-size:clamp(1.2rem,2.3vw,1.5rem);
  line-height:1.4;
  letter-spacing:-.01em;
  margin:0 0 .8rem;
  color:var(--purple);
}
main h3{
  font-family:'Fira Code',monospace;
  font-size:1.08rem;
  line-height:1.5;
  margin:1.3rem 0 .5rem;
  color:var(--brown);
}
main h2 span,main h3 span{position:relative;display:inline-block}
main h2 span::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  bottom:-5px;
  height:6px;
  border-radius:999px;
  background:linear-gradient(90deg,rgba(139,69,19,.38),rgba(86,34,139,.16));
}
main article > section p,
main article > section li{max-width:70ch}
main article > section p{margin:0 0 .9rem}
main article > section li{margin-bottom:.4rem}
main article > section ul,
main article > section ol{padding-left:1.2rem;margin:0 0 .9rem}
main article > section blockquote{
  margin:1rem 0;
  padding:.6rem 1rem;
  border-left:4px solid var(--brown);
  border-radius:0 14px 14px 0;
  background:#f7efe3;
  color:var(--ink-2);
}

/* 右侧目录 */
.side{
  position:sticky;
  top:1.2rem;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:22px 18px 22px 18px;
  padding:1rem .9rem;
}
.side-title{
  font-family:'Fira Code',monospace;
  font-size:1rem;
  margin:0 0 .6rem;
  color:var(--brown);
  letter-spacing:.04em;
}
.toc{list-style:none;margin:0;padding:0;display:flex;flex-direction:column}
.toc a{
  display:block;
  min-height:40px;
  padding:.5rem .45rem;
  font-size:1rem;
  line-height:1.4;
  color:var(--ink-2);
  text-decoration:none;
  border-bottom:1px dashed var(--line);
  border-radius:10px;
}
.toc li:last-child a{border-bottom:0}
.toc a:hover{color:var(--purple);background:#f5ece1}
.toc li.hide{display:none}

/* 页脚三栏 dl */
footer{
  margin-left:var(--rail);
  padding:2rem clamp(1rem,3vw,2rem) 1.4rem;
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,#f2ebdf,#eee5d8);
}
.foot-top{max-width:1080px;margin:0 auto}
.foot-brand{
  font-family:'Fira Code',monospace;
  font-size:1.12rem;
  margin:0 0 1rem;
  color:var(--purple);
}
.foot-cols{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:1.4rem;
}
.foot-cols dl{margin:0}
.foot-cols dt{
  font-family:'Fira Code',monospace;
  font-size:.95rem;
  letter-spacing:.12em;
  color:var(--brown);
  margin-bottom:.35rem;
}
.foot-cols dd{
  margin:0;
  font-size:1rem;
  color:var(--ink-2);
  overflow-wrap:anywhere;
}
.foot-cols dd a{
  display:block;
  min-height:40px;
  padding:.42rem 0;
  color:var(--ink-2);
  text-decoration:none;
  border-bottom:1px solid rgba(220,207,187,.75);
}
.foot-cols dd a:last-child{border-bottom:0}
.foot-cols dd a:hover{color:var(--purple)}
.foot-bar{
  max-width:1080px;
  margin:1.5rem auto 0;
  padding-top:1rem;
  border-top:1px dashed var(--line);
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:.3rem;
  text-align:center;
  font-size:.95rem;
  color:var(--ink-2);
}
.foot-bar p{margin:0}
.foot-bar a{
  display:inline-flex;
  align-items:center;
  min-height:40px;
  padding:.4rem .8rem;
  color:var(--purple);
  text-decoration:none;
  border:1px solid var(--line);
  border-radius:999px;
  background:var(--paper);
}
.foot-bar a:hover{background:#fff}

/* 动效 */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s ease}
.reveal.is-in{opacity:1;transform:none}

@media (max-width:980px){
  .rail{
    position:sticky;
    inset:auto;
    top:0;
    width:auto;
    flex-direction:row;
    flex-wrap:wrap;
    align-items:center;
    gap:.5rem;
    padding:.6rem .8rem;
    border-right:0;
    border-bottom:1px solid var(--line);
    overflow:visible;
  }
  .brand{order:1;min-height:44px}
  .search{order:2;flex:1 1 130px}
  .rail-nav{order:3;width:100%;overflow-x:auto}
  .rail-nav ul{flex-direction:row;gap:.3rem;padding-bottom:.2rem}
  .rail-nav a{white-space:nowrap;min-height:44px;padding:.4rem .8rem}
  .stage{
    margin-left:0;
    grid-template-columns:minmax(0,1fr);
    padding-top:1rem;
  }
  .side{position:static;order:2}
  footer{margin-left:0}
  .hero{
    grid-template-columns:1fr;
    min-height:0;
    gap:1rem;
    padding-top:.6rem;
  }
  .hero-copy{text-align:left}
  .lede{margin-left:0;text-align:left;max-width:none}
  .hero-media{min-height:44vh;order:2}
  main article > section{scroll-margin-top:140px}
  .foot-cols{grid-template-columns:1fr 1fr}
}

@media (max-width:560px){
  .foot-cols{grid-template-columns:1fr}
  .hero-media{min-height:38vh}
  .tile-a{inset:0 12% 22% 0}
  .tile-b{width:44%}
}

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

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