:root{
  --bg:#FAFAFB; --bg2:#F2F2F5;
  --ink:#111114; --ink2:#3B3C42; --mute:#70737C; --faint:#B5B8C0;
  --line:rgba(17,17,20,.08); --line2:rgba(17,17,20,.18);
  --glow:#7C5CD6; --glow-rgb:124,92,214;
  /* 拉丁字体在前:英文 / 数字走 General Sans,中文落到思源黑体子集 */
  --sc:"General Sans","Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  --disp:"Clash Display","General Sans",sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,monospace;
  --ease:cubic-bezier(.2,.7,.2,1);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
section[id]{scroll-margin-top:72px}
body{background:var(--bg); color:var(--ink); font-family:var(--sc); font-weight:400; line-height:1.75;
  -webkit-font-smoothing:antialiased; -moz-osx-font-smoothing:grayscale; overflow-x:hidden}
a{color:inherit}
::selection{background:rgba(var(--glow-rgb),.22); color:var(--ink)}
.wrap{max-width:1280px; margin:0 auto; padding:0 48px}

/* ── nav:首屏透明,滚动后磨砂 ── */
nav{position:fixed; top:0; left:0; right:0; z-index:40; border-bottom:1px solid transparent;
  transition:background .45s, border-color .45s}
nav.scrolled{background:rgba(250,250,251,.72); backdrop-filter:blur(16px) saturate(1.1); -webkit-backdrop-filter:blur(16px) saturate(1.1);
  border-bottom-color:rgba(17,17,20,.06)}
.nav-inner{max-width:1280px; margin:0 auto; padding:18px 48px; display:flex; align-items:center; justify-content:space-between; position:relative}
.logo{display:flex; align-items:center; gap:11px; text-decoration:none; color:var(--ink)}
.logo .mark{width:26px; height:26px; flex:0 0 auto}
.mark .core{fill:var(--glow)}
.logo .co{font-size:15px; font-weight:500; letter-spacing:.3em; line-height:1; transform:translateX(.15em)}
.nav-links{position:absolute; left:50%; top:50%; transform:translate(-50%,-50%); display:flex; gap:32px}
.nav-links a{position:relative; font-size:13px; letter-spacing:.16em; color:var(--mute); text-decoration:none; padding:4px 0; transition:color .25s; white-space:nowrap}
.nav-links a:hover,.nav-links a.act{color:var(--ink)}
.nav-links a::after{content:""; position:absolute; left:0; right:0; bottom:-1px; height:1px; background:var(--glow); opacity:0; transform:scaleX(.4); transition:.35s var(--ease)}
.nav-links a.act::after{opacity:.85; transform:none}
.nav-cta{font-size:12.5px; letter-spacing:.14em; color:var(--ink); text-decoration:none; border:1px solid var(--line2); border-radius:999px; padding:8px 16px; transition:.3s; white-space:nowrap}
.nav-cta:hover{border-color:rgba(var(--glow-rgb),.6); box-shadow:0 0 24px rgba(var(--glow-rgb),.14)}

/* ── hero ── */
#hero{position:relative; height:100vh; min-height:640px; overflow:hidden; background:var(--bg) /* main.js 用 setBackgroundColor 把场景底色设成同一值 */}
.hero-poster{position:absolute; inset:0; background:var(--bg) url(../img/hero-poster.jpg) center/cover no-repeat; transition:opacity 1.4s ease}
#hero.scene-on .hero-poster{opacity:0}
#scene{position:absolute; inset:0; width:100%; height:100%; display:block; opacity:0; transition:opacity 1.4s ease}
#hero.scene-on #scene{opacity:1}
/* 丝带与文案整体下沉:场景画布与海报同步平移,顶部露出的是同色黑底 */
#scene,.hero-poster{transform:translateY(7vh)}
#hero::after{content:""; position:absolute; left:0; right:0; bottom:0; height:160px; pointer-events:none;
  background:linear-gradient(180deg, rgba(250,250,251,0), var(--bg))}
.hero-copy{position:absolute; left:0; right:0; top:44%; transform:translateY(-50%); text-align:center; padding:0 24px; pointer-events:none}
.hero-copy a{pointer-events:auto}
/* wordmark:Readex Pro ExtraLight(与 Spline 场景里原标语同一字体),宽字距,银白 → 尾部银紫;渐变 10s 缓慢呼吸 */
h1{font-family:'Readex Pro',var(--disp); font-weight:250; font-size:clamp(60px,8.6vw,122px); line-height:1; letter-spacing:.34em; color:var(--ink);
  transition:letter-spacing 1.8s var(--ease); padding-left:.2em /* 抵消末字母后的字距,视觉居中 */}
html.hero-ready h1{letter-spacing:.2em}
.wm-big{display:inline-block; background:linear-gradient(100deg,#111114 0%,#26242C 38%,#4B3F8A 62%,#7C5CD6 84%,#9A7FE4 100%);
  background-size:150% 100%; background-position:0% 50%; -webkit-background-clip:text; background-clip:text; color:transparent;
  animation:sheen 10s ease-in-out infinite alternate}
@keyframes sheen{0%{background-position:0% 50%} 100%{background-position:100% 50%}}
.lead{margin:20px auto 0; max-width:720px; font-weight:300; font-size:clamp(15px,1.3vw,19px); color:var(--ink2); letter-spacing:.04em; line-height:1.8}
.hero-actions{display:flex; gap:14px; justify-content:center; margin-top:34px}
.btn{display:inline-flex; align-items:center; height:46px; padding:0 26px; border-radius:999px; font-size:13.5px; letter-spacing:.14em; text-decoration:none; transition:.3s var(--ease); white-space:nowrap}
.btn-p{background:var(--ink); color:#FFFFFF; font-weight:500}
.btn-p:hover{box-shadow:0 10px 32px rgba(var(--glow-rgb),.28); transform:translateY(-1px)}
.btn-g{border:1px solid var(--line2); color:var(--ink)}
.btn-g:hover{border-color:rgba(17,17,20,.45)}
/* 一次编排的入场:场景就绪(或兜底 3s)后错落上浮 */
.hero-copy > *{opacity:0; transform:translateY(18px); transition:opacity 1s var(--ease), transform 1s var(--ease)}
html.hero-ready .hero-copy > *{opacity:1; transform:none}
html.hero-ready .hero-copy h1{transition-delay:.05s}
html.hero-ready .hero-copy .lead{transition-delay:.22s}
html.hero-ready .hero-copy .hero-actions{transition-delay:.38s}
.scroll-cue{position:absolute; left:50%; bottom:26px; width:1px; height:52px; overflow:hidden; opacity:0; transition:opacity 1s 1.2s}
html.hero-ready .scroll-cue{opacity:.8}
.scroll-cue i{position:absolute; left:0; top:-52px; width:1px; height:52px; background:linear-gradient(180deg, transparent, var(--ink2)); animation:cue 2.4s ease-in-out infinite}
@keyframes cue{0%{top:-52px} 60%{top:52px} 100%{top:52px}}

/* ── 章节骨架:左栏主张 sticky,右栏内容 ── */
.sec{padding:128px 0; position:relative}
.two{display:grid; grid-template-columns:5fr 7fr; gap:72px; align-items:start}
.col-h{position:sticky; top:118px}
h2{font-weight:200; font-size:clamp(30px,3.2vw,46px); line-height:1.32; letter-spacing:.02em}
.nw{white-space:nowrap}
.sec-sub{margin-top:18px; color:var(--mute); font-weight:300; font-size:16px; max-width:420px; letter-spacing:.02em}

/* 分隔线:hairline + 随滚动前进的流光 */
.divider{position:relative; height:1px; background:var(--line); overflow:hidden}
.divider::after{content:""; position:absolute; top:0; width:260px; height:1px; left:calc(var(--p,0) * 100% - 130px);
  background:linear-gradient(90deg, transparent, var(--glow), transparent); opacity:.9}

/* ── 业务账页 ── */
.ledger{border-top:1px solid var(--line)}
.row{position:relative; padding:38px 0 38px 30px; border-bottom:1px solid var(--line); display:flex; flex-direction:column; gap:12px}
.row::before{content:""; position:absolute; left:0; top:40px; bottom:40px; width:1px; background:var(--line2); transition:background .45s, box-shadow .45s}
.row:hover::before{background:var(--glow); box-shadow:0 0 14px rgba(var(--glow-rgb),.55)}
.row h3{font-weight:300; font-size:clamp(22px,2vw,28px); line-height:1.3; letter-spacing:.03em; transition:color .3s}
.row p{color:var(--ink2); font-weight:300; font-size:15.5px; max-width:640px; letter-spacing:.01em}
.tags{display:flex; flex-wrap:wrap; gap:6px 20px; margin-top:4px}
.tags span{font-family:var(--mono); font-size:11.5px; letter-spacing:.08em; color:var(--mute); line-height:2}
.tags span:lang(zh){font-family:var(--sc); font-size:12px}

/* ── 合作方式:流光线 + 四节点 ── */
.rail{position:relative; padding-top:38px}
.rail-line{position:absolute; left:0; right:0; top:12px; height:1px; background:var(--line2); overflow:hidden}
.rail-line i{position:absolute; left:0; top:0; height:1px; width:0; background:linear-gradient(90deg, rgba(var(--glow-rgb),.15), var(--glow)); transition:width 1.8s var(--ease)}
.rail.on .rail-line i{width:100%}
.steps{display:grid; grid-template-columns:repeat(4,1fr); gap:32px}
.step{position:relative}
.step::before{content:""; position:absolute; left:0; top:-30px; width:7px; height:7px; border-radius:50%; background:var(--bg); border:1px solid var(--ink2);
  box-shadow:0 0 0 5px var(--bg); transition:background .5s, border-color .5s, box-shadow .5s}
.rail.on .step::before{background:var(--glow); border-color:var(--glow); box-shadow:0 0 0 5px var(--bg), 0 0 12px rgba(var(--glow-rgb),.6)}
.rail.on .step:nth-child(1)::before{transition-delay:.25s}
.rail.on .step:nth-child(2)::before{transition-delay:.7s}
.rail.on .step:nth-child(3)::before{transition-delay:1.15s}
.rail.on .step:nth-child(4)::before{transition-delay:1.6s}
.step h3{font-weight:400; font-size:20px; letter-spacing:.14em}
.step p{margin-top:10px; color:var(--mute); font-weight:300; font-size:14.5px; line-height:1.8}

/* ── 关于 ── */
.about-p{font-weight:300; font-size:18px; color:var(--ink2); line-height:1.95; max-width:640px; letter-spacing:.01em}
.facts{margin-top:48px; border-top:1px solid var(--line)}
.facts > div{display:grid; grid-template-columns:120px 1fr; padding:18px 0; border-bottom:1px solid var(--line); font-size:15px}
.facts dt{font-family:var(--mono); font-size:11.5px; letter-spacing:.14em; color:var(--mute); padding-top:5px}
.facts dd a{color:var(--ink); text-decoration:none; border-bottom:1px solid var(--line2); transition:border-color .3s}
.facts dd a:hover{border-color:var(--glow)}

/* ── 联系 ── */
.contact{text-align:center; padding:168px 0 176px}
.contact h2{font-size:clamp(28px,3vw,40px)}
.big-mail{display:inline-block; margin-top:28px; font-family:var(--disp); font-weight:500; font-size:clamp(30px,5.2vw,68px); letter-spacing:.01em; text-decoration:none;
  background:linear-gradient(100deg,#111114 0%,#2E2C36 55%,#6B4FC4 100%); -webkit-background-clip:text; background-clip:text; color:transparent; transition:filter .45s}
.big-mail:hover{filter:drop-shadow(0 6px 22px rgba(var(--glow-rgb),.35))}
.contact-note{margin-top:22px; color:var(--mute); font-weight:300; font-size:14.5px; letter-spacing:.03em}

/* ── footer ── */
footer{border-top:1px solid var(--line); padding:40px 0 46px}
.foot{display:flex; justify-content:space-between; align-items:flex-end; gap:24px; flex-wrap:wrap}
.foot .co{display:block; font-size:14px; letter-spacing:.3em; font-weight:500}
.foot small{display:block; margin-top:8px; color:var(--mute); font-size:12.5px; letter-spacing:.06em}
.foot-r{display:flex; flex-direction:column; align-items:flex-end; gap:6px; font-family:var(--mono); font-size:11.5px; letter-spacing:.08em; color:var(--mute)}
.foot-r a{color:var(--mute); text-decoration:none; transition:color .3s}
.foot-r a:hover{color:var(--ink)}

/* ── 滚动显现 ── */
.rv{opacity:0; transform:translateY(22px); transition:opacity .95s var(--ease), transform .95s var(--ease)}
.rv.on{opacity:1; transform:none}

/* ── 颗粒 ── */
#grain{position:fixed; inset:0; pointer-events:none; z-index:50; opacity:.035; background-size:240px 240px;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='240' height='240'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .5 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E")}

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  .rv,.hero-copy > *{opacity:1!important; transform:none!important; transition:none!important}
  h1{letter-spacing:.2em; transition:none}
  .wm-big{animation:none; background-position:50% 50%}
  .scroll-cue{display:none}
  .rail-line i{transition:none} .step::before{transition:none}
}

/* ── 响应式 ── */
@media (max-width: 1100px){
  .two{grid-template-columns:4fr 7fr; gap:48px}
}
@media (max-width: 960px){
  .two{grid-template-columns:1fr; gap:44px}
  .col-h{position:static}
  .rail{padding-top:0; padding-left:26px}
  .rail-line{top:4px; bottom:4px; left:0; right:auto; width:1px; height:auto}
  .rail-line i{width:1px; height:0}
  .rail.on .rail-line i{width:1px; height:100%}
  .steps{grid-template-columns:1fr; gap:36px}
  .step::before{top:9px; left:-29px}
}
@media (max-width: 760px){
  .wrap{padding:0 20px}
  .nav-inner{padding:16px 20px}
  .nav-links{display:none}
  #hero{height:88vh; min-height:560px}
  #scene{display:none}
  .hero-copy{top:41%}
  #scene,.hero-poster{transform:translateY(6vh)}
  .lead br{display:none}
  h1{font-size:clamp(44px,13vw,60px); letter-spacing:.3em; padding-left:.18em}
  html.hero-ready h1{letter-spacing:.18em}
  .lead{font-size:15px}
  .hero-actions{flex-direction:column; align-items:center; gap:12px; margin-top:32px}
  .sec{padding:84px 0}
  .row{padding:30px 0 30px 20px}
  .row::before{top:32px; bottom:32px}
  .facts > div{grid-template-columns:1fr; gap:4px}
  .contact{padding:120px 0 128px}
  .foot-r{align-items:flex-start}
}