/* USUTeck 官网共享样式 — 首页与产品介绍页 */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:'Segoe UI','Microsoft YaHei','PingFang SC',sans-serif;background:#0a0e17;color:#c8d6e5;line-height:1.7;overflow-x:hidden}
a{color:#00d4ff;text-decoration:none}
img,picture{max-width:100%;display:block}
img{width:100%;height:auto}

.nav{position:fixed;top:0;left:0;right:0;z-index:1000;background:rgba(10,14,23,.92);backdrop-filter:blur(12px);border-bottom:1px solid rgba(0,212,255,.15);padding:0 2rem;height:64px;display:flex;align-items:center;justify-content:space-between}
.nav-logo{font-size:1.25rem;font-weight:700;color:#fff;letter-spacing:.5px}
.nav-logo span{color:#00d4ff}
.nav-links{display:flex;gap:1.75rem;list-style:none}
.nav-links a{color:#8899aa;font-size:.9rem;font-weight:500;transition:color .25s}
.nav-links a:hover,.nav-links a.active{color:#00d4ff}
.nav-cta{background:linear-gradient(135deg,#00d4ff,#0066ff);color:#fff;border:none;padding:.55rem 1.4rem;border-radius:6px;font-weight:600;font-size:.88rem;cursor:pointer;transition:transform .2s,box-shadow .2s}
.nav-cta:hover{transform:translateY(-1px);box-shadow:0 4px 20px rgba(0,212,255,.35)}
.nav-toggle{display:none;background:none;border:0;color:#00d4ff;font-size:1.4rem;cursor:pointer;line-height:1}

.hero{min-height:auto;display:flex;align-items:center;justify-content:center;text-align:center;position:relative;overflow:hidden;padding:7.5rem 2rem 4rem}
.hero::before{content:'';position:absolute;inset:0;background:radial-gradient(ellipse at 50% 0%,rgba(0,212,255,.12) 0%,transparent 60%),radial-gradient(ellipse at 80% 80%,rgba(0,102,255,.08) 0%,transparent 50%);pointer-events:none}
.hero-grid{display:grid;grid-template-columns:1fr 1fr;gap:4rem;max-width:1200px;width:100%;align-items:center;text-align:left}
.hero-badge{display:inline-block;background:rgba(0,212,255,.12);border:1px solid rgba(0,212,255,.25);color:#00d4ff;padding:.3rem 1rem;border-radius:50px;font-size:.82rem;font-weight:600;margin-bottom:1.5rem;letter-spacing:1px}
.hero h1{font-size:3rem;font-weight:800;color:#fff;line-height:1.2;margin-bottom:1rem}
.hero h1 span{background:linear-gradient(135deg,#00d4ff,#0088ff);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-desc{font-size:1.1rem;color:#8899aa;margin-bottom:2rem;max-width:540px}
.hero-stats{display:flex;gap:2.5rem;margin-bottom:2rem}
.hero-stats dt{font-size:2rem;font-weight:800;color:#00d4ff}
.hero-stats dd{font-size:.82rem;color:#667788;margin-top:.25rem}
.hero-actions{display:flex;gap:1rem;flex-wrap:wrap}
.btn-primary{background:linear-gradient(135deg,#00d4ff,#0066ff);color:#fff;border:none;padding:.75rem 2rem;border-radius:8px;font-weight:600;font-size:.95rem;cursor:pointer;transition:all .25s;text-decoration:none;display:inline-block}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 8px 30px rgba(0,212,255,.4)}
.btn-ghost{border:1.5px solid rgba(0,212,255,.4);color:#00d4ff;background:transparent;padding:.7rem 1.8rem;border-radius:8px;font-weight:600;font-size:.92rem;cursor:pointer;transition:all .25s;text-decoration:none;display:inline-block}
.btn-ghost:hover{background:rgba(0,212,255,.08);border-color:#00d4ff}
.hero-img{position:relative}
.hero-img img{border-radius:16px;box-shadow:0 20px 60px rgba(0,0,0,.5);border:1px solid rgba(255,255,255,.06);aspect-ratio:1536/1024;object-fit:cover}

.section{padding:5rem 2rem;max-width:1200px;margin:0 auto}
.section-header{text-align:center;margin-bottom:4rem}
.section-label{display:inline-block;color:#00d4ff;font-size:.82rem;font-weight:700;letter-spacing:2px;text-transform:uppercase;margin-bottom:.75rem}
.section-header h2{font-size:2.2rem;color:#fff;font-weight:700;margin-bottom:.75rem}
.section-header p{color:#8899aa;max-width:680px;margin:0 auto;font-size:1.02rem}

.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:1.5rem}
.cards-4{grid-template-columns:repeat(4,1fr)}
.card{background:rgba(255,255,255,.03);border:1px solid rgba(255,255,255,.06);border-radius:12px;padding:2rem;transition:all .3s;position:relative;overflow:hidden}
.card::before{content:'';position:absolute;top:0;left:0;right:0;height:3px;background:linear-gradient(90deg,transparent,rgba(0,212,255,.4),transparent);opacity:0;transition:opacity .3s}
.card:hover{transform:translateY(-4px);border-color:rgba(0,212,255,.2);box-shadow:0 12px 40px rgba(0,0,0,.4)}
.card:hover::before{opacity:1}
.card-icon{font-size:2rem;margin-bottom:1rem}
.card h3{color:#fff;font-size:1.1rem;margin-bottom:.6rem}
.card p{color:#8899aa;font-size:.9rem;line-height:1.65}
.card-tag{display:inline-block;background:rgba(0,212,255,.08);color:#00aacc;padding:.15rem .6rem;border-radius:4px;font-size:.75rem;margin-top:.8rem;font-weight:600;margin-right:.35rem}
.card .more{display:inline-block;margin-top:.9rem;font-size:.85rem;font-weight:600;color:#00d4ff}
a.card{color:inherit;display:block}
a.card h3{color:#fff}
a.card p{color:#8899aa}

.two-col{display:grid;grid-template-columns:1fr 1fr;gap:3rem;align-items:center}
.two-col-reverse{direction:rtl}
.two-col-reverse>*{direction:ltr}
.col-text h2{font-size:1.8rem;color:#fff;font-weight:700;margin-bottom:1.2rem}
.col-text p{color:#8899aa;margin-bottom:1.2rem;font-size:1.02rem}
.col-text strong{color:#c8d6e5}
.col-img img{border-radius:12px;box-shadow:0 16px 48px rgba(0,0,0,.45);border:1px solid rgba(255,255,255,.06);aspect-ratio:1536/1024;object-fit:cover;width:100%;height:auto}

.module-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:.75rem}
.module-item{background:rgba(255,255,255,.025);border:1px solid rgba(255,255,255,.05);border-radius:8px;padding:1rem;text-align:center;transition:all .25s}
.module-item:hover{background:rgba(0,212,255,.06);border-color:rgba(0,212,255,.15)}
.module-item .code{font-size:.82rem;font-weight:700;color:#00d4ff;margin-bottom:.2rem}
.module-item .name{font-size:.8rem;color:#8899aa}
a.module-item{color:inherit;display:block}

.highlight-bar{background:linear-gradient(135deg,rgba(0,212,255,.08),rgba(0,102,255,.05));border:1px solid rgba(0,212,255,.12);border-radius:12px;padding:2.5rem;text-align:center;margin:3rem 0}
.highlight-bar h3{color:#fff;font-size:1.4rem;margin-bottom:.5rem}
.highlight-bar p{color:#8899aa;font-size:1rem;max-width:700px;margin:0 auto}

.value-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:1.5rem}
.value-item{display:flex;gap:1.2rem;padding:1.5rem;background:rgba(255,255,255,.02);border-radius:10px;border:1px solid rgba(255,255,255,.04);transition:all .3s}
.value-item:hover{border-color:rgba(0,212,255,.15);background:rgba(255,255,255,.035)}
.value-icon{flex-shrink:0;width:44px;height:44px;display:flex;align-items:center;justify-content:center;background:rgba(0,212,255,.1);border-radius:10px;font-size:1.3rem}
.value-text h4{color:#fff;font-size:1rem;margin-bottom:.3rem}
.value-text p{color:#8899aa;font-size:.88rem}

.footer{text-align:center;padding:3rem 2rem;border-top:1px solid rgba(255,255,255,.05);color:#556677;font-size:.85rem}
.footer strong{color:#8899aa}
.footer-beian{display:flex;flex-wrap:wrap;justify-content:center;align-items:center;gap:.25rem .9rem;margin-top:.7rem}
.footer-beian a{color:#667788;display:inline-flex;align-items:center;gap:.35rem;font-size:.82rem}
.footer-beian a:hover{color:#00d4ff}
.beian-badge{width:16px;height:16px;flex-shrink:0}

.divider{height:1px;background:linear-gradient(90deg,transparent,rgba(0,212,255,.15),transparent);max-width:800px;margin:0 auto}

.crumbs{font-size:.85rem;color:#667788;margin-bottom:1.25rem}
.crumbs a{color:#8899aa}
.crumbs a:hover{color:#00d4ff}
.crumbs .sep{margin:0 .45rem;color:#445566}
.audience{display:flex;flex-wrap:wrap;gap:.5rem;margin:1.2rem 0 0}
.audience span{background:rgba(0,212,255,.08);border:1px solid rgba(0,212,255,.15);color:#00d4ff;padding:.2rem .7rem;border-radius:50px;font-size:.78rem;font-weight:600}
.product-note{color:#667788;font-size:.88rem;margin-top:.4rem}
.hero.product-hero h1{font-size:2.55rem}

@media(max-width:1024px){
  .cards-4{grid-template-columns:repeat(2,1fr)}
  .nav-links{gap:1.1rem}
}
@media(max-width:768px){
  .hero-grid,.two-col{grid-template-columns:1fr;gap:2.5rem}
  .hero h1,.hero.product-hero h1{font-size:2rem}
  .hero-stats{flex-wrap:wrap;gap:1.4rem}
  .cards,.cards-4{grid-template-columns:1fr}
  .module-grid{grid-template-columns:repeat(2,1fr)}
  .value-grid{grid-template-columns:1fr}
  .nav-toggle{display:block}
  .nav-links{
    display:none;position:absolute;top:64px;left:0;right:0;
    flex-direction:column;gap:0;background:rgba(10,14,23,.97);
    border-bottom:1px solid rgba(0,212,255,.15);padding:.5rem 0
  }
  .nav-links.open{display:flex}
  .nav-links a{display:block;padding:.85rem 2rem}
  .nav-cta{display:none}
}