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

:root{
  --paper:#fafaf8;
  --ink:#1a1a1a;
  --grey:#4a4a4a;
  --rule:rgba(26,26,26,.24);
  --soft:0 1px 0 rgba(26,26,26,.1),0 16px 32px -24px rgba(26,26,26,.8);
}

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

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

body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:'IBM Plex Sans',system-ui,-apple-system,'Segoe UI',Arial,sans-serif;
  font-size:17px;
  line-height:1.68;
  font-weight:400;
  overflow-x:hidden;
}

body::after{
  content:'';
  position:fixed;
  inset:0;
  z-index:9;
  pointer-events:none;
  opacity:.15;
  mix-blend-mode:multiply;
  background-repeat:repeat;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='p'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.86' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='160' height='160' filter='url(%23p)'/%3E%3C/svg%3E");
}

a{color:var(--ink);text-decoration:none}
img{max-width:100%;height:auto}

/* ===== 顶部 ===== */
.masthead{
  position:sticky;
  top:0;
  z-index:20;
  background:rgba(250,250,248,.97);
  border-bottom:1.5px solid var(--ink);
}

.mast-row{
  max-width:1120px;
  margin:0 auto;
  padding:12px 22px 10px;
  display:flex;
  align-items:center;
  gap:14px;
  flex-wrap:wrap;
}

.brand{
  display:inline-block;
  padding:10px 0;
  font-size:18px;
  font-weight:600;
  letter-spacing:.015em;
  line-height:1.1;
  border-bottom:2.5px solid var(--ink);
}

.find{
  display:flex;
  align-items:center;
  gap:5px;
  margin-left:auto;
  padding:3px 4px 3px 12px;
  background:#fff;
  border:1.5px solid var(--ink);
  border-radius:16px 22px 16px 22px/22px 16px 22px 16px;
}

.find-q{
  width:118px;
  border:0;
  background:transparent;
  color:var(--ink);
  font:inherit;
  font-size:16px;
  padding:9px 0;
  outline:none;
}

.find-go{
  min-height:40px;
  border:0;
  cursor:pointer;
  padding:9px 12px;
  font:inherit;
  font-size:15px;
  background:var(--ink);
  color:var(--paper);
  border-radius:12px 16px 12px 16px/16px 12px 16px 12px;
}

.jump{position:relative}

.jump summary{
  display:inline-block;
  padding:11px 14px;
  cursor:pointer;
  list-style:none;
  font-size:16px;
  line-height:1.4;
  border:1.5px solid var(--ink);
  border-radius:14px 18px 14px 18px/18px 14px 18px 14px;
}

.jump summary::-webkit-details-marker{display:none}

.jump-body{
  position:absolute;
  right:0;
  top:calc(100% + 8px);
  z-index:30;
  display:flex;
  gap:22px;
  min-width:236px;
  padding:16px 18px;
  background:#fff;
  border:1.5px solid var(--ink);
  border-radius:22px 16px 24px 16px/16px 24px 16px 22px;
  box-shadow:var(--soft);
}

.jump-p{
  margin:0;
  display:flex;
  flex-direction:column;
  gap:1px;
}

.jump-p a{
  display:block;
  padding:9px 6px;
  font-size:16px;
  border-bottom:1px dashed var(--rule);
}

.rail{
  overflow-x:auto;
  border-top:1.5px dashed var(--rule);
  scrollbar-width:none;
}

.rail::-webkit-scrollbar{display:none}

.rail p{
  margin:0;
  padding:0 14px;
  display:flex;
  gap:1px;
  white-space:nowrap;
}

.rail a{
  display:inline-block;
  padding:12px 10px;
  font-size:16px;
  color:var(--grey);
  border-bottom:2.5px solid transparent;
}

.rail a:hover,
.rail a.on{
  color:var(--ink);
  border-bottom-color:var(--ink);
}

/* ===== 主区 ===== */
.sheet{
  max-width:1120px;
  margin:0 auto;
  padding:0 22px 70px;
  display:grid;
  grid-template-columns:minmax(0,1fr) 252px;
  gap:40px;
  align-items:start;
}

.hero{
  grid-column:1/-1;
  position:relative;
  display:grid;
  grid-template-columns:1.2fr .8fr;
  gap:28px;
  align-items:center;
  min-height:45vh;
  padding:30px 0 34px;
  border-bottom:2px solid var(--ink);
  overflow:hidden;
}

.hero.bare{grid-template-columns:1fr}

.hero::before{
  content:'01';
  position:absolute;
  top:-8px;
  left:-10px;
  z-index:0;
  font-size:clamp(88px,19vw,180px);
  font-weight:700;
  line-height:.85;
  letter-spacing:-.07em;
  color:rgba(26,26,26,.08);
}

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

.hero h1{
  margin:0;
  font-size:clamp(26px,4.6vw,44px);
  line-height:1.22;
  font-weight:600;
  letter-spacing:-.01em;
}

.hero-fig{
  position:relative;
  z-index:1;
  margin:0;
  overflow:hidden;
  background:#fff;
  border:1.5px solid var(--ink);
  border-radius:28px 22px 30px 20px/20px 30px 22px 28px;
  box-shadow:var(--soft);
  transform:rotate(-1.4deg);
}

.hero-fig img{
  display:block;
  width:100%;
  filter:grayscale(1) contrast(1.06);
}

.paper{min-width:0}

.paper > section{
  padding:36px 0;
  border-bottom:1px dashed var(--rule);
  scroll-margin-top:128px;
}

.paper > section:last-child{border-bottom:0}
.paper > section.hit{outline:2px dashed var(--ink);outline-offset:8px}

.paper h2{
  margin:0 0 .55em;
  font-size:clamp(21px,2.7vw,27px);
  line-height:1.3;
  font-weight:600;
  letter-spacing:-.01em;
}

.paper h3{
  margin:1.5em 0 .4em;
  font-size:18px;
  font-weight:600;
}

.paper p{margin:0 0 1em}
.paper p:last-child{margin-bottom:0}

.paper a{
  color:var(--ink);
  text-decoration:underline;
  text-decoration-color:var(--grey);
  text-decoration-thickness:1.5px;
  text-underline-offset:3px;
}

.paper ul,
.paper ol{
  margin:0 0 1em;
  padding-left:1.35em;
}

.paper li{margin:.32em 0}

.paper blockquote{
  margin:1.2em 0;
  padding:12px 18px;
  background:#f1f1ec;
  border-left:3px solid var(--ink);
  font-style:italic;
}

.paper img{
  border-radius:20px;
  filter:grayscale(1);
}

.paper figure{margin:1.3em 0}
.paper figcaption{font-size:16px;color:var(--grey);margin-top:.4em}

.paper table{
  width:100%;
  border-collapse:collapse;
  font-size:16px;
  margin:0 0 1em;
}

.paper th,
.paper td{
  padding:9px 8px;
  text-align:left;
  border-bottom:1px solid var(--rule);
}

.paper th{
  font-weight:600;
  border-bottom:2px solid var(--ink);
}

/* ===== 侧栏 ===== */
.side{
  position:sticky;
  top:128px;
  padding:20px 18px;
  background:#fff;
  border:1.5px solid var(--ink);
  border-radius:28px 20px 26px 18px/18px 26px 20px 28px;
  box-shadow:var(--soft);
  transform:rotate(.6deg);
}

.side-h{
  margin:0 0 6px;
  font-size:17px;
  font-weight:600;
  letter-spacing:.01em;
}

.side .subtitle{
  margin:0 0 14px;
  font-size:16px;
  line-height:1.6;
  color:var(--grey);
}

.side-nav{
  list-style:none;
  margin:0;
  padding:0;
  border-top:1.5px dashed var(--rule);
}

.side-nav li{border-bottom:1px dashed var(--rule)}
.side-nav a{display:block;padding:11px 2px;font-size:16px}
.side-nav a:hover{background:#f1f1ec}

/* ===== 页脚 ===== */
.site-foot{
  margin-top:20px;
  background:#f3f3ef;
  border-top:2px solid var(--ink);
}

.cta{
  max-width:1120px;
  margin:0 auto;
  padding:44px 22px 34px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:20px;
  flex-wrap:wrap;
  border-bottom:1.5px dashed var(--rule);
}

.cta-word{
  margin:0;
  font-size:clamp(24px,4vw,40px);
  font-weight:600;
  line-height:1.14;
  letter-spacing:-.02em;
  transform:rotate(-.8deg);
}

.cta-go{
  display:inline-block;
  padding:13px 22px;
  font-size:16px;
  background:var(--ink);
  color:var(--paper);
  border:1.5px solid var(--ink);
  border-radius:18px 24px 18px 24px/24px 18px 24px 18px;
}

.foot-cols{
  max-width:1120px;
  margin:0 auto;
  padding:30px 22px;
  display:grid;
  grid-template-columns:1.3fr 1fr 1fr .9fr;
  gap:24px;
}

.foot-addr{
  font-style:normal;
  font-size:16px;
  font-weight:600;
  line-height:1.55;
}

.foot-list{
  list-style:none;
  margin:0;
  padding:0;
}

.foot-list a{
  display:block;
  padding:9px 0;
  font-size:16px;
  border-bottom:1px dashed var(--rule);
}

.foot-end{margin:0}

.foot-end a{
  display:inline-block;
  padding:9px 0;
  font-size:16px;
  text-decoration:underline;
  text-underline-offset:3px;
}

.copy{
  max-width:1120px;
  margin:0 auto;
  padding:16px 22px 26px;
  text-align:center;
  font-size:16px;
  color:var(--grey);
  border-top:1.5px solid var(--rule);
}

/* ===== 动效 ===== */
.rv{opacity:0;transform:translateY(12px) rotate(-.5deg)}

.rv.in{
  opacity:1;
  transform:none;
  transition:opacity .3s steps(4,end),transform .3s ease-out;
}

/* ===== 窄屏 ===== */
@media (max-width:860px){
  .sheet{grid-template-columns:1fr;gap:26px}
  .side{position:static;transform:rotate(-.5deg)}
  .hero{grid-template-columns:1fr;gap:20px}
  .foot-cols{grid-template-columns:1fr 1fr}
  .find-q{width:92px}
}

@media (max-width:520px){
  .mast-row{padding:10px 16px 8px;gap:10px}
  .brand{font-size:17px}
  .find{order:3;width:100%;margin-left:0}
  .find-q{width:100%}
  .jump{margin-left:auto}
  .jump-body{flex-direction:column;gap:10px;min-width:0;width:min(74vw,260px)}
  .rail p{padding:0 10px}
  .sheet{padding:0 16px 50px}
  .hero{padding:22px 0 26px}
  .paper > section{scroll-margin-top:150px}
  .foot-cols{grid-template-columns:1fr;gap:18px}
  .cta{padding:32px 16px 26px}
  .copy{padding:14px 16px 24px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .rv{opacity:1;transform:none;transition:none}
  .rv.in{transition:none}
  .hero-fig,.side,.cta-word{transform:none}
}

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