:root{
  --ink:#1f1f1f;
  --paper:#ffffff;
  --stone:#f5f5f5;
  --line:#e2e2e2;
  --muted:#6b6b6b;
  --mono:'Space Mono',ui-monospace,SFMono-Regular,'Courier New',monospace;
  --e1:0 1px 2px rgba(31,31,31,.08),0 2px 6px rgba(31,31,31,.06);
  --e2:0 6px 16px rgba(31,31,31,.10),0 2px 5px rgba(31,31,31,.07);
  --e3:0 14px 34px rgba(31,31,31,.14),0 5px 12px rgba(31,31,31,.08);
  --e4:0 26px 62px rgba(31,31,31,.22),0 10px 22px rgba(31,31,31,.10);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
html.locked,html.locked body{overflow:hidden}
body{
  margin:0;
  padding-bottom:98px;
  background:var(--stone);
  color:var(--ink);
  font-family:system-ui,-apple-system,'PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  font-size:16px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
small{display:block;font-family:var(--mono);font-size:13px;letter-spacing:.18em;color:#8d8d8d}
h1,h2,h3,h4{font-family:var(--mono);font-weight:700;letter-spacing:-.01em}
a{color:var(--ink)}
.skip{
  position:absolute;left:12px;top:-80px;z-index:90;
  background:var(--ink);color:var(--paper);text-decoration:none;
  padding:12px 16px;border-radius:10px;font-size:16px;
  transition:top .2s ease;
}
.skip:focus{top:12px}

/* ---------- 层叠门面 ---------- */
.hero{
  position:relative;
  isolation:isolate;
  overflow:hidden;
  min-height:70vh;
  display:flex;
  flex-direction:column;
  justify-content:center;
  gap:20px;
  padding:64px 22px 52px;
  background:linear-gradient(158deg,#fff 0%,#f7f7f7 55%,#ededed 100%);
  border-bottom:1px solid var(--line);
}
.hero::before{
  content:"";
  position:absolute;
  right:-70px;top:-70px;
  width:280px;height:280px;
  border:1px solid #e4e4e4;
  border-radius:50%;
  z-index:0;
}
.hero::after{
  content:"";
  position:absolute;
  left:-90px;bottom:-120px;
  width:320px;height:320px;
  background:#fff;
  opacity:.55;
  border-radius:10px;
  transform:rotate(12deg);
  box-shadow:var(--e2);
  z-index:0;
}
.hero-bg{
  position:absolute;
  left:-.04em;bottom:-.16em;
  z-index:0;
  font-family:var(--mono);
  font-weight:700;
  font-size:clamp(3.2rem,15vw,11rem);
  line-height:.8;
  letter-spacing:-.03em;
  color:transparent;
  -webkit-text-stroke:1.5px #dedede;
  white-space:nowrap;
  pointer-events:none;
  will-change:transform;
}
.hero-copy{position:relative;z-index:3;max-width:660px}
.hero h1{
  margin:0 0 20px;
  font-size:clamp(2rem,6.4vw,3.5rem);
  line-height:1.18;
  text-shadow:0 1px 0 #fff;
}
.hero-lede{
  margin:0;
  max-width:33em;
  color:#3f3f3f;
  background:rgba(255,255,255,.68);
  backdrop-filter:blur(6px);
  -webkit-backdrop-filter:blur(6px);
  padding:13px 16px;
  border-left:3px solid var(--ink);
  border-radius:0 10px 10px 0;
  box-shadow:var(--e1);
}
.hero-stack{
  position:absolute;
  right:5vw;top:50%;
  transform:translateY(-50%);
  width:min(36%,360px);
  z-index:2;
}
.hero-img{
  display:block;
  width:100%;
  height:auto;
  border-radius:10px;
  border:4px solid #fff;
  background:#ececec;
}
.hero-img-a{position:relative;z-index:3;box-shadow:var(--e4);transform:rotate(-2.2deg)}
.hero-img-b{position:absolute;z-index:2;left:-24%;bottom:-18%;width:74%;box-shadow:var(--e3);transform:rotate(3.6deg)}

/* ---------- 正文骨架 ---------- */
.shell{
  display:grid;
  grid-template-columns:222px minmax(0,1fr);
  gap:30px;
  align-items:start;
  max-width:1160px;
  margin:0 auto;
  padding:36px 22px 64px;
}
.rail{position:sticky;top:20px;z-index:2}
.rail-card{
  position:relative;
  background:var(--paper);
  border-radius:10px;
  border-bottom:3px solid var(--ink);
  padding:18px 16px 22px;
  box-shadow:var(--e3);
}
.rail-card h2{font-size:18px;margin:6px 0 0;line-height:1.3}
.rail-list{list-style:none;counter-reset:rail;margin:14px 0 0;padding:0;display:grid;gap:2px}
.rail-list li{counter-increment:rail}
.rail-list a{
  display:flex;
  gap:9px;
  align-items:baseline;
  padding:9px 6px;
  font-size:16px;
  line-height:1.45;
  color:#333;
  text-decoration:none;
  border-radius:8px;
}
.rail-list a::before{
  content:counter(rail,decimal-leading-zero);
  font-family:var(--mono);
  font-size:13px;
  color:#a2a2a2;
}
.rail-list a:hover{background:var(--stone);color:#000}

.stream{position:relative;z-index:1;min-width:0}
.stream > article{
  position:relative;
  background:var(--paper);
  border-radius:10px;
  border-bottom:3px solid var(--ink);
  box-shadow:var(--e2);
  padding:26px 24px 32px;
  margin:0 0 26px;
  scroll-margin-top:22px;
  overflow:hidden;
  transition:box-shadow .45s ease,transform .45s cubic-bezier(.22,.7,.28,1);
}
.stream > article:nth-child(even){margin-left:14px}
.stream > article.in{box-shadow:var(--e4)}
.stream h2{
  margin:8px 0 14px;
  font-size:clamp(1.35rem,3.4vw,1.9rem);
  line-height:1.28;
}
.stream h3,.stream h4{margin:1.5em 0 .55em;font-size:1.12rem;line-height:1.35}
.stream p{margin:0 0 1em}
.stream ul,.stream ol{padding-left:1.4em;margin:0 0 1em}
.stream li{margin:.32em 0}
.stream a{color:var(--ink);text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:3px}
.stream a:hover{background:#f0f0f0}
.stream blockquote{
  margin:1.2em 0;
  padding:12px 16px;
  background:var(--stone);
  border-left:3px solid var(--ink);
  border-radius:0 10px 10px 0;
}
.stream img{display:block;max-width:100%;height:auto;border-radius:10px;box-shadow:var(--e2)}
.stream figure{margin:1.3em 0}
.stream figcaption{font-size:15px;color:var(--muted);margin-top:8px}
.stream table{width:100%;border-collapse:collapse;font-size:16px;margin:1.2em 0}
.stream th,.stream td{border-bottom:1px solid var(--line);padding:10px 8px;text-align:left;vertical-align:top}
.stream th{font-family:var(--mono);font-size:15px;background:var(--stone)}
.stream code,.stream pre{font-family:var(--mono);font-size:15px}
.stream pre{overflow:auto;background:#f0f0f0;padding:14px;border-radius:10px}
.stream hr{border:0;border-top:1px solid var(--line);margin:2em 0}

/* ---------- 页脚 ---------- */
.foot{
  position:relative;
  z-index:2;
  display:grid;
  grid-template-columns:1.4fr 1fr 1fr 1fr;
  gap:26px;
  background:var(--paper);
  border-top:1px solid var(--line);
  box-shadow:0 -18px 44px rgba(31,31,31,.07);
  padding:46px max(22px,calc((100% - 1120px)/2)) 22px;
}
.foot h3{font-size:16px;line-height:1.4;margin:8px 0 6px;word-break:break-word}
.foot-desc{margin:10px 0 0;font-size:15px;line-height:1.65;color:var(--muted);max-width:22em}
.foot-nav dl{display:grid;grid-template-columns:2.2rem minmax(0,1fr);gap:0 8px;margin:8px 0 0}
.foot-nav dt{font-family:var(--mono);font-size:13px;color:#a6a6a6;padding-top:14px}
.foot-nav dd{margin:0}
.foot-nav dd a{display:inline-flex;align-items:center;min-height:40px;padding:4px 0;text-decoration:none;font-size:16px;color:#2c2c2c}
.foot-list{list-style:none;margin:8px 0 0;padding:0;display:grid;gap:2px}
.foot-list a{display:inline-flex;align-items:center;min-height:40px;padding:4px 0;text-decoration:none;font-size:16px;color:#2c2c2c}
.foot-top{display:inline-flex;align-items:center;min-height:40px;margin-top:8px;padding:4px 0;font-size:16px;color:#2c2c2c}
.foot-nav dd a:hover,.foot-list a:hover,.foot-top:hover{text-decoration:underline;text-underline-offset:4px}
.foot-bottom{
  grid-column:1 / -1;
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  justify-content:space-between;
  align-items:center;
  border-top:1px solid #ececec;
  margin-top:12px;
  padding-top:16px;
  font-family:var(--mono);
  font-size:14px;
  color:var(--muted);
}
.foot-bottom a{display:inline-flex;align-items:center;min-height:40px;padding:4px 0;text-decoration:none;color:#2c2c2c}

/* ---------- 底部固定条 ---------- */
.bar{
  position:fixed;
  inset:auto 0 0 0;
  z-index:50;
  display:flex;
  align-items:center;
  gap:6px;
  padding:9px 14px;
  background:rgba(255,255,255,.88);
  backdrop-filter:blur(16px) saturate(150%);
  -webkit-backdrop-filter:blur(16px) saturate(150%);
  border-top:1px solid var(--line);
  box-shadow:0 -10px 30px rgba(31,31,31,.12);
}
.bar-links{display:flex;align-items:center;gap:2px;min-width:0}
.bar-link{
  font-size:16px;
  padding:11px 9px;
  min-height:42px;
  display:inline-flex;
  align-items:center;
  color:#3a3a3a;
  text-decoration:none;
  border-radius:10px;
  white-space:nowrap;
}
.bar-link:hover{background:#f0f0f0;color:#000}
.bar-brand{
  margin:0 auto;
  padding:9px 8px;
  font-family:var(--mono);
  font-weight:700;
  font-size:16px;
  color:var(--ink);
  text-decoration:none;
  white-space:nowrap;
  box-shadow:0 1px 0 var(--ink);
}
.bar-cta{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:11px 16px;
  margin-left:4px;
  background:var(--ink);
  color:var(--paper);
  text-decoration:none;
  border-radius:10px;
  font-size:16px;
  white-space:nowrap;
  box-shadow:var(--e3);
}
.bar-cta:hover{background:#000}
.bar-burger{
  flex:0 0 auto;
  width:44px;height:44px;
  display:inline-flex;
  flex-direction:column;
  justify-content:center;
  align-items:center;
  gap:4px;
  padding:0;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:10px;
  box-shadow:var(--e1);
  cursor:pointer;
}
.bar-burger span{display:block;width:18px;height:2px;background:var(--ink);border-radius:2px}

/* ---------- 全屏菜单 ---------- */
.sheet{
  position:fixed;
  inset:0;
  z-index:60;
  display:grid;
  grid-template-rows:auto 1fr;
  gap:18px;
  padding:18px 22px 34px;
  background:rgba(245,245,245,.96);
  backdrop-filter:blur(20px);
  -webkit-backdrop-filter:blur(20px);
  opacity:0;
  visibility:hidden;
  transition:opacity .28s ease,visibility .28s ease;
}
.sheet.on{opacity:1;visibility:visible}
.sheet-head{display:flex;align-items:center;justify-content:space-between;gap:12px}
.sheet-brand{font-family:var(--mono);font-weight:700;font-size:16px}
.sheet-close{
  min-height:44px;
  padding:11px 18px;
  font-size:16px;
  font-family:inherit;
  color:var(--ink);
  background:var(--paper);
  border:1px solid var(--ink);
  border-radius:10px;
  box-shadow:var(--e2);
  cursor:pointer;
}
.sheet-nav{align-self:center;overflow:auto;max-width:760px;width:100%;margin:0 auto}
.sheet-nav ul{list-style:none;margin:0;padding:0;display:grid;gap:2px}
.sheet-nav a{
  display:block;
  padding:14px 6px;
  min-height:52px;
  font-family:var(--mono);
  font-size:clamp(1.05rem,3.6vw,1.5rem);
  color:var(--ink);
  text-decoration:none;
  border-bottom:1px solid #dedede;
}
.sheet-nav a:hover{background:#ededed}

/* ---------- 动效 ---------- */
@media (prefers-reduced-motion: no-preference){
  .stream > article{animation:rise .62s cubic-bezier(.22,.7,.28,1) both}
  .stream > article:nth-child(1){animation-delay:.02s}
  .stream > article:nth-child(2){animation-delay:.08s}
  .stream > article:nth-child(3){animation-delay:.14s}
  .stream > article:nth-child(4){animation-delay:.2s}
  .stream > article:nth-child(5){animation-delay:.26s}
  .stream > article:nth-child(6){animation-delay:.32s}
  .stream > article:nth-child(7){animation-delay:.38s}
  .hero-copy{animation:fadein .6s ease both}
  @keyframes rise{from{opacity:0;transform:translateY(22px)}to{opacity:1;transform:none}}
  @keyframes fadein{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:none}}
}
@media (prefers-reduced-motion: reduce){
  .stream > article{transition:none}
}

/* ---------- 断点 ---------- */
@media (max-width:1080px){
  .bar-link{font-size:15px;padding:11px 7px}
}
@media (max-width:920px){
  .bar-links{display:none}
  .shell{grid-template-columns:190px minmax(0,1fr);gap:22px}
  .foot{grid-template-columns:1fr 1fr;gap:22px}
}
@media (max-width:820px){
  .hero{min-height:0;padding:56px 20px 44px}
  .hero-stack{
    position:relative;
    right:auto;top:auto;
    transform:none;
    width:100%;
    max-width:340px;
    margin:26px 0 0;
    padding-bottom:26px;
  }
  .hero-img-b{left:auto;right:-4%;bottom:0;width:60%}
  .hero-bg{font-size:clamp(3rem,17vw,7rem)}
}
@media (max-width:760px){
  body{padding-bottom:92px}
  .shell{grid-template-columns:minmax(0,1fr);gap:0;padding:26px 18px 52px}
  .rail{position:static;order:-1;margin-bottom:22px}
  .rail-card{padding:14px 14px 16px}
  .rail-list{grid-template-columns:1fr 1fr;gap:2px 8px}
  .rail-list a{font-size:15px;padding:8px 5px}
  .stream > article{padding:22px 17px 26px;margin-bottom:20px}
  .stream > article:nth-child(even){margin-left:0}
  .foot{grid-template-columns:1fr;gap:18px;padding:36px 18px 26px}
  .foot-desc{max-width:none}
  .bar{padding:8px 12px;gap:8px}
  .bar-brand{font-size:15px}
  .bar-cta{padding:11px 13px;font-size:15px;margin-left:0}
  .sheet-nav a{font-size:1.1rem}
}
@media (max-width:380px){
  .bar-brand{letter-spacing:-.02em}
  .hero h1{font-size:1.85rem}
}

/* ---------- 打印 ---------- */
@media print{
  .bar,.sheet,.skip{display:none}
  body{background:#fff;padding:0}
  .stream > article{box-shadow:none;border:1px solid #ddd;break-inside:avoid}
  .rail{display:none}
  .shell{display:block}
}

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