:root{--navy:#0F2B5B;--navy-2:#173A75;--navy-3:#0A1F42;--accent:#FF6B2C;--accent-dark:#E85A1C;--accent-soft:#FFF1E9;--bg:#F6F8FC;--text:#1A2332;--muted:#5A6B85;--line:#E3E9F2;--white:#fff;--green:#10B981;--radius:14px;--shadow:0 4px 24px rgba(15,43,91,.08);--shadow-lg:0 12px 40px rgba(15,43,91,.14);}
*{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{font-family:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;color:var(--text);background:var(--white);line-height:1.65;-webkit-font-smoothing:antialiased;}
a{text-decoration:none;color:inherit;}
img{max-width:100%;display:block;}
ul{list-style:none;}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit;}
input,textarea{font-family:inherit;}
.container{max-width:1200px;margin:0 auto;padding:0 24px;}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:14px 30px;border-radius:10px;font-size:16px;font-weight:600;border:none;cursor:pointer;transition:.25s;white-space:nowrap;}
.btn-primary{background:var(--accent);color:#fff;box-shadow:0 6px 20px rgba(255,107,44,.32);}
.btn-primary:hover{background:var(--accent-dark);transform:translateY(-2px);box-shadow:0 10px 26px rgba(255,107,44,.42);}
.btn-ghost{background:transparent;color:#fff;border:1.5px solid rgba(255,255,255,.45);}
.btn-ghost:hover{background:rgba(255,255,255,.12);border-color:#fff;}
@media (max-width:768px){.container{padding:0 18px;}}
.topbar{background:var(--navy-3);color:rgba(255,255,255,.78);font-size:13px;padding:8px 0;text-align:center;letter-spacing:.2px;}
.topbar strong{color:#FFB88C;font-weight:600;}
.header{position:sticky;top:0;z-index:1000;background:rgba(255,255,255,.94);backdrop-filter:blur(14px);border-bottom:1px solid var(--line);transition:.3s;}
.header.scrolled{box-shadow:0 4px 20px rgba(15,43,91,.07);}
.nav{display:flex;align-items:center;justify-content:space-between;height:70px;}
.logo{display:flex;align-items:center;gap:10px;font-size:21px;font-weight:800;color:var(--navy);letter-spacing:-.4px;flex-shrink:0;}
.logo-mark{width:36px;height:36px;border-radius:9px;flex-shrink:0;background:linear-gradient(135deg,var(--navy) 0%,var(--navy-2) 100%);display:flex;align-items:center;justify-content:center;color:#fff;font-size:15px;font-weight:800;}
.logo-mark::after{content:"US";}
.logo .sub{font-size:11px;font-weight:500;color:var(--muted);letter-spacing:1.5px;display:block;margin-top:-4px;}
.nav-links{display:flex;align-items:center;gap:24px;}
.nav-links > a,.nav-drop > a{font-size:15px;font-weight:500;color:var(--text);transition:.2s;position:relative;padding:6px 0;display:inline-flex;align-items:center;gap:4px;}
.nav-links > a:hover,.nav-drop > a:hover,.nav-links > a.active{color:var(--accent);}
.nav-links > a::after,.nav-drop > a::after{content:"";position:absolute;left:0;bottom:-2px;width:0;height:2px;background:var(--accent);transition:.28s;}
.nav-links > a:hover::after,.nav-drop:hover > a::after,.nav-links > a.active::after{width:100%;}
.caret{font-size:10px;transition:.25s;}
.nav-drop{position:relative;}
.nav-drop:hover .caret{transform:rotate(180deg);}
.drop-menu{position:absolute;top:calc(100% + 14px);left:50%;transform:translateX(-50%) translateY(8px);width:220px;background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:0 16px 44px rgba(15,43,91,.14);padding:10px;opacity:0;visibility:hidden;transition:.25s;z-index:10;}
.drop-menu::before{content:"";position:absolute;top:-6px;left:50%;transform:translateX(-50%) rotate(45deg);width:12px;height:12px;background:#fff;border-left:1px solid var(--line);border-top:1px solid var(--line);}
.nav-drop:hover .drop-menu{opacity:1;visibility:visible;transform:translateX(-50%) translateY(0);}
.drop-menu a{display:block;padding:10px 14px;border-radius:9px;font-size:14px;color:var(--text);transition:.2s;}
.drop-menu a:hover{background:var(--accent-soft);color:var(--accent);}
.nav-actions{display:flex;align-items:center;gap:14px;flex-shrink:0;}
.nav-actions .btn{padding:11px 22px;font-size:15px;}
.menu-toggle{display:none;font-size:24px;color:var(--navy);cursor:pointer;padding:4px 8px;}
@media (max-width:1024px){.nav-links{gap:16px;}.nav-links > a,.nav-drop > a{font-size:14px;}}
@media (max-width:768px){.nav-links{display:none;position:absolute;top:70px;left:0;right:0;background:#fff;flex-direction:column;gap:0;align-items:stretch;padding:8px 0;border-bottom:1px solid var(--line);box-shadow:0 12px 30px rgba(15,43,91,.1);max-height:calc(100vh - 70px);overflow-y:auto;}.nav-links.active{display:flex;}.nav-links > a,.nav-drop > a{padding:15px 24px;width:100%;border-bottom:1px solid var(--line);font-size:15px;}.nav-links > a::after,.nav-drop > a::after{display:none;}.nav-drop{width:100%;}.drop-menu{position:static;transform:none;opacity:1;visibility:visible;width:100%;box-shadow:none;border:none;border-radius:0;padding:0;background:var(--bg);}.drop-menu::before{display:none;}.drop-menu a{padding:13px 40px;border-bottom:1px solid var(--line);border-radius:0;}.menu-toggle{display:block;}.topbar{font-size:12px;padding:7px 14px;}}
.footer{background:#071733;color:rgba(255,255,255,.6);padding:66px 0 0;font-size:14px;}
.footer-grid{display:grid;grid-template-columns:1.6fr 1fr 1fr 1.3fr;gap:44px;padding-bottom:48px;}
.footer h4{font-size:15px;color:#fff;font-weight:700;margin-bottom:20px;}
.footer-links li{margin-bottom:11px;}
.footer-links a{transition:.2s;}
.footer-links a:hover{color:var(--accent);}
.footer-brand .logo{color:#fff;margin-bottom:18px;}
.footer-brand p{line-height:1.9;font-size:13.5px;margin-bottom:20px;}
.footer-contact li{margin-bottom:13px;display:flex;gap:10px;line-height:1.7;font-size:13.5px;}
.footer-contact b{color:rgba(255,255,255,.85);font-weight:600;}
.footer-bottom{border-top:1px solid rgba(255,255,255,.09);padding:22px 0;display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:12px;font-size:13px;}
.footer-bottom a:hover{color:var(--accent);}
@media (max-width:1024px){.footer-grid{grid-template-columns:1fr 1fr;gap:36px;}}
@media (max-width:768px){.footer-grid{grid-template-columns:1fr;gap:32px;}.footer-bottom{flex-direction:column;text-align:center;}}

/* ============ 悬浮按钮组 ============ */
.float-btn{
  position:fixed;
  right:24px;
  bottom:100px;
  z-index:960;
  display:flex;
  flex-direction:column;
  gap:12px;
}

/* 单个按钮项 */
.float-item{
  position:relative;
}
.float-link{
  width:54px;
  height:54px;
  border-radius:16px;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  background:#fff;
  box-shadow:0 8px 24px rgba(15,43,91,.18);
  font-size:10.5px;
  font-weight:600;
  color:var(--navy);
  transition:.25s;
  gap:2px;
  cursor:pointer;
  text-decoration:none;
}
.float-link:hover{
  transform:translateY(-4px);
  box-shadow:0 12px 30px rgba(15,43,91,.26);
}
.float-link .ico{
  font-size:19px;
  line-height:1;
}

/* 微信：橙色 */
.float-link.wx{
  background:var(--accent);
  color:#fff;
}

/* WhatsApp：绿色 */
.float-link.wa{
  background:#25D366;
  color:#fff;
}

/* 返回顶部：深蓝 */
.float-link.top{
  background:var(--navy);
  color:#fff;
  opacity:0;
  visibility:hidden;
  transform:translateY(10px);
  transition:opacity .3s, visibility .3s, transform .3s;
}
.float-link.top.show{
  opacity:1;
  visibility:visible;
  transform:translateY(0);
}
.float-link.top:hover{
  background:var(--navy-2);
}

/* ============ 微信悬浮二维码 ============ */
.wx-qrcode{
  position:absolute;
  right:calc(100% + 14px);
  top:50%;
  transform:translateY(-50%) translateX(8px);
  opacity:0;
  visibility:hidden;
  transition:.3s;
  pointer-events:none;
}
.float-item:hover .wx-qrcode{
  opacity:1;
  visibility:visible;
  transform:translateY(-50%) translateX(0);
  pointer-events:auto;
}
.wx-qrcode-inner{
  background:#fff;
  border-radius:14px;
  padding:16px 16px 14px;
  box-shadow:0 12px 40px rgba(15,43,91,.18);
  text-align:center;
  width:180px;
  position:relative;
}
.wx-qrcode-inner::after{
  content:"";
  position:absolute;
  right:-6px;
  top:50%;
  transform:translateY(-50%) rotate(45deg);
  width:12px;
  height:12px;
  background:#fff;
  box-shadow:2px -2px 6px rgba(15,43,91,.06);
}
.wx-qrcode-inner img{
  width:140px;
  height:140px;
  border-radius:8px;
  margin:0 auto 10px;
  display:block;
  object-fit:cover;
  background:var(--bg);
}
.wx-qrcode-tip{
  font-size:12.5px;
  font-weight:700;
  color:var(--navy);
  margin-bottom:4px;
}
.wx-qrcode-id{
  font-size:11.5px;
  color:var(--muted);
  font-family:"Helvetica Neue",Arial,sans-serif;
}

/* ============ 微信大图弹窗 ============ */
.wx-modal{
  position:fixed;
  inset:0;
  z-index:1500;
  display:flex;
  align-items:center;
  justify-content:center;
  padding:24px;
  opacity:0;
  visibility:hidden;
  transition:.3s;
}
.wx-modal.open{
  opacity:1;
  visibility:visible;
}
.wx-modal-mask{
  position:absolute;
  inset:0;
  background:rgba(10,31,66,.6);
  backdrop-filter:blur(3px);
}
.wx-modal-box{
  position:relative;
  background:#fff;
  border-radius:18px;
  padding:32px 32px 26px;
  width:100%;
  max-width:360px;
  text-align:center;
  transform:translateY(20px) scale(.96);
  transition:.35s;
  box-shadow:0 24px 70px rgba(10,31,66,.3);
}
.wx-modal.open .wx-modal-box{
  transform:translateY(0) scale(1);
}
.wx-modal-close{
  position:absolute;
  top:14px;
  right:14px;
  width:32px;
  height:32px;
  border-radius:9px;
  background:var(--bg);
  font-size:19px;
  color:var(--muted);
  display:flex;
  align-items:center;
  justify-content:center;
  cursor:pointer;
  transition:.2s;
  line-height:1;
}
.wx-modal-close:hover{
  background:var(--accent);
  color:#fff;
}
.wx-modal-box h3{
  font-size:19px;
  font-weight:800;
  color:var(--navy);
  margin-bottom:6px;
  letter-spacing:-.3px;
}
.wx-modal-sub{
  font-size:13px;
  color:var(--muted);
  margin-bottom:20px;
}
.wx-modal-qr{
  width:220px;
  height:220px;
  margin:0 auto 18px;
  background:var(--bg);
  border-radius:14px;
  display:flex;
  align-items:center;
  justify-content:center;
  overflow:hidden;
}
.wx-modal-qr img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.wx-modal-id{
  display:flex;
  align-items:center;
  gap:8px;
  background:var(--bg);
  border-radius:10px;
  padding:10px 10px 10px 16px;
  margin-bottom:14px;
}
.wx-modal-id span{
  flex:1;
  font-size:14px;
  font-weight:700;
  color:var(--navy);
  font-family:"Helvetica Neue",Arial,sans-serif;
  text-align:left;
}
.wx-copy-btn{
  flex-shrink:0;
  padding:8px 14px;
  border-radius:7px;
  background:var(--accent);
  color:#fff;
  font-size:12.5px;
  font-weight:700;
  cursor:pointer;
  transition:.2s;
}
.wx-copy-btn:hover{
  background:var(--accent-dark);
}
.wx-copy-btn.copied{
  background:var(--green);
}
.wx-modal-tip{
  font-size:12px;
  color:var(--muted);
  line-height:1.7;
}

/* ============ Toast ============ */
.toast{
  position:fixed;
  left:50%;
  bottom:40px;
  transform:translateX(-50%) translateY(20px);
  background:var(--navy);
  color:#fff;
  font-size:14px;
  font-weight:600;
  padding:13px 24px;
  border-radius:11px;
  z-index:1600;
  box-shadow:0 12px 34px rgba(10,31,66,.32);
  opacity:0;
  visibility:hidden;
  transition:.3s;
  display:flex;
  align-items:center;
  gap:9px;
  max-width:90vw;
}
.toast.show{
  opacity:1;
  visibility:visible;
  transform:translateX(-50%) translateY(0);
}
.toast .dot{
  width:8px;
  height:8px;
  border-radius:50%;
  background:var(--green);
  flex-shrink:0;
}

/* ============ 移动端 ============ */
@media (max-width:768px){
  .float-btn{
    right:14px;
    bottom:18px;
    gap:10px;
  }
  .float-link{
    width:48px;
    height:48px;
    border-radius:14px;
    font-size:10px;
  }
  .float-link .ico{
    font-size:17px;
  }
  /* 移动端不显示悬浮二维码（用点击弹窗代替） */
  .wx-qrcode{
    display:none;
  }
  .wx-modal-box{
    padding:26px 22px 22px;
    max-width:320px;
  }
  .wx-modal-qr{
    width:180px;
    height:180px;
  }
  .toast{
    bottom:24px;
    font-size:13px;
    padding:12px 18px;
  }
}