/* ════════════════════════════════════════════════════════════
   ling · 共享设计系统  base.css
   黑白 · 单色编辑风  (near-black 底 + 白/银灰层次，克制高级)
   所有区块模板统一引用本文件，改一处全局生效。
   ════════════════════════════════════════════════════════════ */
:root{
  --bg:#000000;
  --bg-2:#0A0A0A;
  --surface:rgba(255,255,255,0.04);
  --surface-strong:rgba(255,255,255,0.07);
  --glass-border:rgba(255,255,255,0.12);
  --line:rgba(255,255,255,0.10);
  --line-2:rgba(255,255,255,0.18);
  --text:#F4F4F5;
  --text-2:#A6A6A8;
  --text-3:#6B6B6E;
  --accent:#FFFFFF;   /* 纯白 */
  --accent-2:#D6D6D8; /* 银灰 */
  --accent-3:#9A9A9C; /* 深灰 */
  --grad:linear-gradient(120deg,#FFFFFF 0%,#E4E4E6 50%,#B8B8BB 100%);
  --grad-soft:linear-gradient(120deg,rgba(255,255,255,.14),rgba(255,255,255,.06));
  --serif:'Noto Serif SC',serif;
  --sans:'Inter',-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif;
  --mono:'Inter',ui-monospace,SFMono-Regular,Consolas,monospace;
}
*{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{font-family:var(--sans); color:var(--text); line-height:1.65;
  background:var(--bg); overflow-x:hidden; -webkit-font-smoothing:antialiased; cursor:default;}
::selection{background:rgba(255,255,255,.85); color:#000000;}
::-webkit-scrollbar{width:10px;}
::-webkit-scrollbar-track{background:transparent;}
::-webkit-scrollbar-thumb{background:rgba(255,255,255,.22); border-radius:10px; border:2px solid var(--bg);}

/* 极光流动背景 */
.aurora{position:fixed; inset:0; z-index:-2; overflow:hidden; background:linear-gradient(180deg,var(--bg) 0%,var(--bg-2) 100%);}
.aurora::before,.aurora::after{content:''; position:absolute; inset:-25%;}
.aurora::before{
  background:
    radial-gradient(38% 46% at 18% 22%, rgba(255,255,255,.06), transparent 62%),
    radial-gradient(44% 44% at 82% 18%, rgba(255,255,255,.045), transparent 62%),
    radial-gradient(48% 48% at 62% 82%, rgba(200,200,205,.04), transparent 62%),
    radial-gradient(42% 42% at 24% 76%, rgba(255,255,255,.05), transparent 62%);
  filter:blur(40px); animation:drift 28s ease-in-out infinite alternate;
}
.aurora::after{
  background:
    radial-gradient(34% 34% at 72% 32%, rgba(255,255,255,.04), transparent 62%),
    radial-gradient(40% 40% at 30% 58%, rgba(255,255,255,.03), transparent 62%);
  filter:blur(52px); animation:drift2 36s ease-in-out infinite alternate;
}
@keyframes drift{0%{transform:translate(0,0) scale(1)}100%{transform:translate(4%,3%) scale(1.1)}}
@keyframes drift2{0%{transform:translate(0,0) scale(1.02)}100%{transform:translate(-3%,-4%) scale(1.06)}}
.grain{position:fixed; inset:0; z-index:-1; pointer-events:none; opacity:.035;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");}

/* 全局背景粒子层（铺满整页视口，置于内容之下） */
#motes{position:fixed; inset:0; z-index:0; pointer-events:none;}
main,.section,.starwrap,.cta,.footer,.hero{position:relative; z-index:1;}

/* 玻璃导航 */
.nav{position:fixed; top:0; left:0; right:0; z-index:100;
  background:rgba(0,0,0,0.55); backdrop-filter:saturate(160%) blur(22px); -webkit-backdrop-filter:saturate(160%) blur(22px);
  border-bottom:1px solid transparent; transition:border-color .3s, background .3s;}
.nav.scrolled{border-bottom-color:var(--line); background:rgba(0,0,0,0.82);}
.nav-inner{max-width:1180px; margin:0 auto; height:64px; padding:0 28px; display:flex; align-items:center; justify-content:space-between;}
.logo{display:flex; align-items:center; gap:11px; text-decoration:none;}
.logo .mark{width:30px; height:30px; border-radius:9px; display:grid; place-items:center; font-family:var(--serif); font-size:16px; font-weight:600; color:#000000;
  background:var(--grad); box-shadow:0 4px 14px rgba(255,255,255,.18);}
.logo .word{font-size:19px; font-weight:600; letter-spacing:-.01em; color:var(--text);}
.logo .word em{font-style:normal; background:var(--grad); -webkit-background-clip:text; background-clip:text; color:transparent;}
.nav-links{display:flex; align-items:center; gap:2px;}
.nav-link{font-size:13.5px; color:var(--text-2); text-decoration:none; padding:9px 15px; border-radius:8px; transition:.2s; font-weight:450;}
.nav-link:hover{color:var(--text); background:rgba(255,255,255,.06);}
.nav-cta{font-size:13.5px; font-weight:600; color:#000000; text-decoration:none; padding:9px 20px; border-radius:9px; margin-left:6px;
  background:var(--grad); box-shadow:0 6px 20px rgba(255,255,255,.16); transition:transform .2s, box-shadow .2s;}
.nav-cta:hover{transform:translateY(-1px); box-shadow:0 10px 28px rgba(255,255,255,.24);}

/* 通用按钮 */
.btn{display:inline-flex; align-items:center; gap:10px; text-decoration:none; cursor:pointer; border:none;
  font-family:var(--sans); font-size:15px; font-weight:600; transition:all .25s cubic-bezier(.2,.7,.2,1); position:relative; overflow:hidden;}
.btn-solid{padding:15px 30px; border-radius:11px; background:var(--grad); color:#000000; box-shadow:0 10px 30px rgba(255,255,255,.14);}
.btn-solid:hover{transform:translateY(-2px); box-shadow:0 16px 42px rgba(255,255,255,.22);}
.btn-solid::after{content:''; position:absolute; inset:0; background:linear-gradient(90deg,transparent,rgba(255,255,255,.5),transparent); transform:translateX(-100%); transition:transform .6s;}
.btn-solid:hover::after{transform:translateX(100%);}
.btn-ghost{padding:15px 24px; border-radius:11px; color:var(--text); background:var(--surface-strong); border:1px solid var(--glass-border);
  backdrop-filter:blur(14px); -webkit-backdrop-filter:blur(14px);}
.btn-ghost:hover{border-color:var(--line-2); transform:translateY(-1px); box-shadow:0 8px 24px rgba(255,255,255,.06);}
.btn .arrow{transition:transform .25s;}
.btn:hover .arrow{transform:translateX(3px);}

/* 玻璃卡 */
.glass{background:var(--surface); backdrop-filter:blur(24px) saturate(160%); -webkit-backdrop-filter:blur(24px) saturate(160%);
  border:1px solid var(--glass-border); box-shadow:0 18px 50px rgba(0,0,0,.45);}

/* reveal 动效 */
.reveal{opacity:0; transform:translateY(26px); transition:opacity .7s, transform .7s cubic-bezier(.2,.7,.2,1);}
.reveal.in{opacity:1; transform:none;}

/* 通用区块间距 */
.section{padding:118px 0; position:relative;}
.wrap{max-width:1180px; margin:0 auto; padding:0 28px;}
.section-head{max-width:720px; margin-bottom:64px;}
.eyebrow{display:inline-flex; align-items:center; gap:8px; font-size:12px; letter-spacing:.18em; text-transform:uppercase; font-weight:600;
  background:var(--grad); -webkit-background-clip:text; background-clip:text; color:transparent; margin-bottom:18px;}
.section-head h2{font-family:var(--serif); font-weight:500; font-size:clamp(30px,4.4vw,46px); letter-spacing:-.02em; line-height:1.18; color:var(--text);}
.section-head p{margin-top:16px; font-size:16px; color:var(--text-2); line-height:1.85;}