/* Stardust International — 官网样式（零外链，全自托管） */
:root{
  --blue-900:#082A47;
  --blue-700:#0B3B66;
  --blue-600:#0E4D92;
  --teal:#14A6A0;
  --teal-dark:#0E8683;
  --ink:#1C2B36;
  --muted:#5A6B7A;
  --bg:#F4F8FB;
  --card:#FFFFFF;
  --line:#DCE6EE;
  --radius:14px;
  --shadow:0 8px 28px rgba(8,42,71,.10);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Segoe UI",Arial,sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
.container{max-width:1120px;margin:0 auto;padding:0 24px}

/* ===== Header ===== */
.site-header{
  position:sticky;top:0;z-index:100;
  background:linear-gradient(90deg,var(--blue-900) 0%,var(--blue-700) 60%,#0C4A6E 100%);
  color:#fff;box-shadow:0 2px 12px rgba(8,42,71,.25);
}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:68px;gap:16px}
.brand{display:flex;align-items:center;gap:12px;min-width:0}
.brand img{height:42px;width:auto}
.brand .brand-name{font-size:15px;font-weight:600;letter-spacing:.5px;white-space:nowrap}
.main-nav{display:flex;align-items:center;gap:4px}
.main-nav a{
  padding:8px 14px;border-radius:8px;font-size:14.5px;color:rgba(255,255,255,.85);
  transition:background .2s,color .2s;
}
.main-nav a:hover{background:rgba(255,255,255,.12);color:#fff}
.main-nav a.active{background:rgba(255,255,255,.16);color:#fff;font-weight:600}
.lang-toggle{
  margin-left:8px;border:1px solid rgba(255,255,255,.4);background:transparent;color:#fff;
  padding:6px 14px;border-radius:20px;font-size:13.5px;cursor:pointer;transition:.2s;
}
.lang-toggle:hover{background:rgba(255,255,255,.15)}
.nav-burger{display:none;background:none;border:none;color:#fff;font-size:24px;cursor:pointer;padding:6px}

/* ===== Hero ===== */
.hero{
  position:relative;color:#fff;
  background:
    linear-gradient(100deg,rgba(6,32,56,.92) 0%,rgba(10,60,100,.78) 45%,rgba(14,90,110,.55) 100%),
    url("../img/hero-bg.jpeg") center/cover no-repeat;
}
.hero-inner{padding:110px 0 130px;max-width:760px}
.hero .kicker{
  display:inline-block;font-size:13px;letter-spacing:2.5px;text-transform:uppercase;
  color:#7FE0DB;border:1px solid rgba(127,224,219,.45);padding:5px 14px;border-radius:20px;margin-bottom:22px;
}
.hero h1{font-size:40px;line-height:1.3;font-weight:700;margin-bottom:18px}
.hero h1 .accent{color:#5FD9D3}
.hero p.sub{font-size:17px;color:rgba(255,255,255,.85);max-width:620px;margin-bottom:34px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap}
.btn{
  display:inline-block;padding:12px 30px;border-radius:8px;font-size:15px;font-weight:600;
  transition:transform .15s,box-shadow .15s,background .2s;
}
.btn:active{transform:translateY(1px)}
.btn-primary{background:var(--teal);color:#fff;box-shadow:0 4px 16px rgba(20,166,160,.4)}
.btn-primary:hover{background:var(--teal-dark)}
.btn-ghost{border:1.5px solid rgba(255,255,255,.55);color:#fff}
.btn-ghost:hover{background:rgba(255,255,255,.12)}
.btn-outline{border:1.5px solid var(--teal);color:var(--teal-dark)}
.btn-outline:hover{background:rgba(20,166,160,.08)}

/* ===== Stats strip ===== */
.stats{margin-top:-56px;position:relative;z-index:5}
.stats-grid{
  display:grid;grid-template-columns:repeat(4,1fr);gap:18px;
  background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:30px 24px;
}
.stat{text-align:center}
.stat .num{font-size:32px;font-weight:700;color:var(--blue-600)}
.stat .num small{font-size:16px;font-weight:600}
.stat .label{font-size:13.5px;color:var(--muted);margin-top:4px}

/* ===== Sections ===== */
.section{padding:72px 0}
.section.alt{background:#fff}
.section-head{text-align:center;max-width:680px;margin:0 auto 48px}
.section-head .eyebrow{
  font-size:13px;letter-spacing:2px;text-transform:uppercase;color:var(--teal-dark);font-weight:700;margin-bottom:10px;
}
.section-head h2{font-size:30px;color:var(--blue-900);margin-bottom:12px}
.section-head p{color:var(--muted);font-size:15.5px}

/* ===== Product cards (home) ===== */
.product-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.product-card{
  background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:28px 24px;
  text-align:center;transition:transform .2s,box-shadow .2s;display:flex;flex-direction:column;gap:12px;
}
.product-card:hover{transform:translateY(-5px);box-shadow:0 14px 34px rgba(8,42,71,.16)}
.product-card .ph{
  width:170px;height:170px;margin:0 auto;border-radius:50%;
  background:radial-gradient(circle at 35% 30%,#10456E,#072A45);
  display:flex;align-items:center;justify-content:center;
}
.product-card .ph img{width:150px;height:150px;object-fit:contain}
.product-card h3{font-size:18px;color:var(--blue-900)}
.product-card .en{font-size:12.5px;color:var(--muted);margin-top:-8px}
.product-card .spec{font-size:13.5px;color:var(--teal-dark);font-weight:600}
.product-card p{font-size:14px;color:var(--muted);flex:1}

/* ===== Feature icons ===== */
.feature-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.feature{
  background:var(--card);border-radius:var(--radius);padding:26px 20px;text-align:center;
  box-shadow:var(--shadow);border-top:3px solid var(--teal);
}
.feature .ico{font-size:30px;margin-bottom:10px}
.feature h4{font-size:16px;color:var(--blue-900);margin-bottom:6px}
.feature p{font-size:13px;color:var(--muted)}

/* ===== Applications ===== */
.app-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.app-item{
  position:relative;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);aspect-ratio:16/9;
}
.app-item img{width:100%;height:100%;object-fit:cover;transition:transform .3s}
.app-item:hover img{transform:scale(1.05)}
.app-item .cap{
  position:absolute;left:0;right:0;bottom:0;padding:26px 14px 10px;color:#fff;font-size:14px;font-weight:600;
  background:linear-gradient(transparent,rgba(6,32,56,.85));
}

/* ===== Product detail pages ===== */
.pd-block{padding:64px 0}
.pd-block:nth-child(even){background:#fff}
.pd-layout{display:grid;grid-template-columns:340px 1fr;gap:44px;align-items:start}
.pd-layout.flip{grid-template-columns:1fr 340px}
.pd-media{position:sticky;top:92px}
.pd-media .circle{
  width:300px;height:300px;margin:0 auto;border-radius:50%;
  background:radial-gradient(circle at 35% 30%,#10456E,#072A45);
  display:flex;align-items:center;justify-content:center;box-shadow:var(--shadow);
}
.pd-media .circle img{width:250px;height:250px;object-fit:contain}
.pd-tag{
  display:inline-block;background:rgba(20,166,160,.12);color:var(--teal-dark);
  font-size:12.5px;font-weight:700;padding:4px 12px;border-radius:14px;margin-bottom:10px;letter-spacing:1px;
}
.pd-title{font-size:27px;color:var(--blue-900);margin-bottom:4px}
.pd-en{font-size:14px;color:var(--muted);margin-bottom:16px}
.pd-desc{font-size:15.5px;margin-bottom:20px}
.pd-h4{font-size:15px;color:var(--blue-700);font-weight:700;margin:22px 0 10px;letter-spacing:1px}
.pd-list{list-style:none}
.pd-list li{
  position:relative;padding-left:22px;font-size:14.5px;color:var(--ink);margin-bottom:8px;
}
.pd-list li::before{content:"";position:absolute;left:2px;top:9px;width:8px;height:8px;border-radius:2px;background:var(--teal)}
.spec-table{
  width:100%;border-collapse:collapse;font-size:14px;background:var(--card);
  border-radius:10px;overflow:hidden;box-shadow:var(--shadow);
}
.spec-table th,.spec-table td{padding:11px 16px;text-align:left;border-bottom:1px solid var(--line)}
.spec-table tr:last-child td{border-bottom:none}
.spec-table th{width:34%;background:#EEF5FA;color:var(--blue-700);font-weight:600}
.app-photos{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:18px}
.app-photos img{border-radius:10px;box-shadow:var(--shadow);width:100%;height:150px;object-fit:cover}

/* ===== About ===== */
.about-layout{display:grid;grid-template-columns:380px 1fr;gap:44px;align-items:center}
.about-layout .photo{border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden}
.patent-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;margin-top:40px}
.patent-card{
  background:linear-gradient(160deg,var(--blue-700),var(--blue-600));color:#fff;
  border-radius:var(--radius);padding:26px 20px;text-align:center;box-shadow:var(--shadow);
}
.patent-card .num{font-size:34px;font-weight:700;color:#5FD9D3}
.patent-card .label{font-size:13.5px;color:rgba(255,255,255,.85);margin-top:6px}

/* ===== Contact ===== */
.contact-grid{display:grid;grid-template-columns:1fr 1.2fr;gap:40px;align-items:start}
.contact-card{
  background:linear-gradient(160deg,var(--blue-700),var(--blue-600));color:#fff;
  border-radius:var(--radius);padding:38px 32px;box-shadow:var(--shadow);
}
.contact-card h3{font-size:20px;margin-bottom:8px}
.contact-card p{font-size:14px;color:rgba(255,255,255,.85);margin-bottom:22px}
.contact-row{display:flex;align-items:center;gap:12px;padding:14px 0;border-top:1px solid rgba(255,255,255,.18);font-size:15px}
.contact-row .ico{font-size:20px}
.contact-row a{color:#5FD9D3;font-weight:600;word-break:break-all}
.form-card{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:34px 32px}
.form-card h3{font-size:19px;color:var(--blue-900);margin-bottom:20px}
.form-field{margin-bottom:16px}
.form-field label{display:block;font-size:13.5px;font-weight:600;color:var(--blue-700);margin-bottom:6px}
.form-field input,.form-field textarea{
  width:100%;padding:11px 14px;border:1.5px solid var(--line);border-radius:8px;font-size:14.5px;
  font-family:inherit;background:#FBFDFE;transition:border .2s;
}
.form-field input:focus,.form-field textarea:focus{outline:none;border-color:var(--teal)}
.form-field textarea{min-height:120px;resize:vertical}
.form-hint{font-size:12.5px;color:var(--muted);margin-top:12px}

/* ===== CTA band ===== */
.cta-band{
  background:linear-gradient(100deg,var(--blue-900),var(--blue-600));color:#fff;text-align:center;padding:64px 24px;
}
.cta-band h2{font-size:26px;margin-bottom:10px}
.cta-band p{color:rgba(255,255,255,.8);margin-bottom:26px}

/* ===== Footer ===== */
.site-footer{background:var(--blue-900);color:rgba(255,255,255,.75);padding:44px 0 26px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:36px;margin-bottom:30px}
.site-footer h5{color:#fff;font-size:15px;margin-bottom:12px}
.site-footer ul{list-style:none}
.site-footer li{margin-bottom:8px;font-size:13.5px}
.site-footer a:hover{color:#5FD9D3}
.footer-logo{display:flex;align-items:center;gap:12px;margin-bottom:12px}
.footer-logo img{height:38px}
.footer-logo span{font-size:15px;font-weight:600;color:#fff}
.footer-bottom{
  border-top:1px solid rgba(255,255,255,.15);padding-top:20px;text-align:center;font-size:12.5px;color:rgba(255,255,255,.5);
}

/* ===== Responsive ===== */
@media (max-width:960px){
  .product-grid{grid-template-columns:repeat(2,1fr)}
  .feature-grid,.app-grid,.patent-grid{grid-template-columns:repeat(2,1fr)}
  .stats-grid{grid-template-columns:repeat(2,1fr);gap:24px}
  .pd-layout,.pd-layout.flip{grid-template-columns:1fr}
  .pd-media{position:static}
  .about-layout{grid-template-columns:1fr}
  .contact-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr 1fr}
  .hero h1{font-size:30px}
}
@media (max-width:640px){
  .product-grid{grid-template-columns:1fr}
  .feature-grid,.app-grid,.patent-grid{grid-template-columns:1fr}
  .nav-burger{display:block}
  .main-nav{
    display:none;position:absolute;top:68px;left:0;right:0;flex-direction:column;
    background:var(--blue-900);padding:14px 20px 20px;gap:6px;box-shadow:0 12px 24px rgba(0,0,0,.3);
  }
  .main-nav.open{display:flex}
  .main-nav a{width:100%;padding:12px 14px}
  .hero-inner{padding:70px 0 100px}
  .section{padding:52px 0}
  .footer-grid{grid-template-columns:1fr}
}