/* ===== 全局基础与导航（白色主色调 · 沉浸式 · 纯灵动标签实现） ===== */
:root{
  --page:#f4f7fc;
  --card:#ffffff;
  --card-2:#f7faff;
  --ink:#17294e;
  --ink-2:#3f5680;
  --ink-3:#8296bb;
  --blue:#0ea5e9;
  --blue-2:#38bdf8;
  --violet:#7b5bff;
  --orange:#ff8a1e;
  --orange-2:#ff9a3d;
  --line:rgba(35,80,160,.14);
  --glass:rgba(255,255,255,.9);
  --glass-2:rgba(255,255,255,.78);
  --grad:linear-gradient(135deg,#0ea5e9 0%,#6366f1 100%);
  --grad-orange:linear-gradient(135deg,#ff8a1e 0%,#ffb056 100%);
  --shadow-lg:0 22px 60px rgba(30,60,120,.14);
  --radius:18px;
  --nav-h:84px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%;overflow-x:clip}
body{font-family:"Noto Sans SC","Source Han Sans SC","思源黑体","PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;background:var(--page);color:var(--ink);line-height:1.7;overflow-x:clip}
img{max-width:100%;border:0;display:block}
a{color:inherit;text-decoration:none;transition:color .25s,background .25s,transform .25s,box-shadow .25s,border-color .25s}
ul,ol{list-style:none}
button{font-family:inherit;cursor:pointer;border:0;background:none;color:inherit}
input,select,textarea{font-family:inherit;font-size:16px}
table{border-collapse:collapse;width:100%}
.container{width:min(1680px,92%);margin:0 auto}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}

/* SVG 资质标识 */
.cert-pre{display:inline-flex;align-items:center;font-size:12.5px;color:var(--ink-2);letter-spacing:.5px;white-space:nowrap}
.cert-set{display:inline-flex;align-items:center;gap:8px}
.cert-set img{height:28px;width:auto}

/* ===== 头部导航（白底毛玻璃） ===== */
.site-header{position:fixed;top:0;left:0;right:0;z-index:900;transition:background .35s,box-shadow .35s;background:linear-gradient(90deg,#0f2f8f 0%,#1a44b8 60%,#1439a2 100%);border-bottom:1px solid rgba(255,255,255,.14)}
.site-header::after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:2px;background:linear-gradient(90deg,transparent,rgba(255,138,30,.8),transparent)}
.site-header.scrolled{box-shadow:0 12px 40px rgba(8,20,60,.45)}
.nav-inner{max-width:1680px;margin:0 auto;padding:0 28px;height:var(--nav-h);display:flex;align-items:center;gap:20px}
.brand{display:flex;align-items:center;gap:13px;flex-shrink:0}
.brand-logo{height:52px;width:auto;background:#fff;border-radius:14px;padding:6px 12px;box-shadow:0 8px 24px rgba(4,16,50,.4);transition:transform .3s,box-shadow .3s}
.brand:hover .brand-logo{transform:translateY(-2px);box-shadow:0 14px 34px rgba(30,60,120,.18)}
.logo-txt{display:inline-flex;align-items:center;height:46px;padding:0 14px;border-radius:12px;background:var(--grad);color:#fff;font-weight:800;font-size:17px;letter-spacing:1px;white-space:nowrap}
.brand-side{display:flex;flex-direction:column;gap:3px}
.brand-side .cert-pre{font-size:11.5px;color:rgba(255,255,255,.75)}
.brand-side .cert-set{gap:5px}
.brand-side .cert-set img{height:20px}
.nav-menu{display:flex;align-items:center;gap:4px;margin:0 auto}
.nav-menu>ul{display:flex;align-items:center;gap:4px}
.nav-item{position:relative}
.nav-item>a{display:flex;align-items:center;gap:6px;height:50px;padding:0 20px;margin:0 2px;font-size:16px;font-weight:600;color:rgba(255,255,255,.88);position:relative;white-space:nowrap;border-radius:999px;transition:background .25s,color .25s}
.nav-item>a::after{content:"";position:absolute;left:50%;bottom:8px;width:0;height:3px;border-radius:2px;background:var(--grad-orange);transform:translateX(-50%);transition:width .3s}
.nav-item:hover>a{color:#fff;background:rgba(255,255,255,.12)}
.nav-item:hover>a::after{width:22px}
.nav-item.active>a{color:#fff;background:rgba(255,255,255,.16)}
.nav-item.active>a::after{width:22px}
.nav-drop-box{position:absolute;top:calc(100% - 6px);left:50%;transform:translate(-50%,12px);width:760px;background:#fff;border:1px solid rgba(255,255,255,.2);border-radius:18px;box-shadow:0 30px 70px rgba(4,16,50,.4);padding:18px;opacity:0;visibility:hidden;transition:opacity .3s,transform .3s,visibility .3s;z-index:50}
.nav-item:hover .nav-drop-box,.nav-item:focus-within .nav-drop-box{opacity:1;visibility:visible;transform:translate(-50%,0)}
.nav-drop-in{display:grid;grid-template-columns:minmax(0,1fr) 218px;gap:16px}
.drop-links{display:grid;grid-template-columns:1fr 1fr;gap:3px}
.drop-links a{display:flex;align-items:center;gap:10px;padding:11px 14px;border-radius:12px;font-size:14.5px;color:var(--ink-2)}
.drop-links a:hover{background:rgba(20,57,162,.08);color:#1439a2}
.drop-links a::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--grad-orange);flex-shrink:0}
.drop-aside{background-color:#1a44b8;background-image:url('https://www.yjssishi.com/skin/imgslot/drop-260x200.webp');background-image:image-set(url('https://www.yjssishi.com/skin/imgslot/drop-260x200.avif') type('image/avif'),url('https://www.yjssishi.com/skin/imgslot/drop-260x200.webp') type('image/webp'));background-size:cover;background-position:center;border-radius:14px;padding:18px 16px;color:#fff;display:flex;flex-direction:column;gap:10px}
.drop-aside .da-t{font-size:14.5px;font-weight:800;display:flex;align-items:center;gap:8px}
.drop-aside .da-t::before{content:"";width:4px;height:16px;border-radius:2px;background:var(--grad-orange)}
.drop-aside p{font-size:12.5px;color:rgba(255,255,255,.82);line-height:1.7}
.drop-aside .da-btn{margin-top:auto;display:inline-flex;align-items:center;justify-content:center;height:38px;border-radius:999px;background:var(--grad-orange);color:#fff;font-size:13px;font-weight:700}
.drop-aside .da-btn:hover{box-shadow:0 8px 22px rgba(255,138,30,.5)}
.nav-drop-box a::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--grad-orange);flex-shrink:0}
.nav-right{display:flex;align-items:center;gap:14px;flex-shrink:0}
.nav-phone{display:flex;align-items:center;gap:9px;color:rgba(255,255,255,.85);font-size:14px;font-weight:600}
.nav-phone svg{width:17px;height:17px;fill:var(--orange)}
.nav-phone strong{color:#fff;font-size:17px;letter-spacing:.5px}
.icon-btn{display:inline-flex;align-items:center;justify-content:center;width:46px;height:46px;border-radius:50%;border:1px solid rgba(255,255,255,.35);color:#fff;background:rgba(255,255,255,.08);transition:transform .25s,box-shadow .25s,color .25s}
.icon-btn:hover{color:#fff;border-color:rgba(255,255,255,.7);background:rgba(255,255,255,.16);transform:translateY(-2px)}
.icon-btn svg{width:19px;height:19px;fill:currentColor}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;border-radius:14px;font-weight:700;letter-spacing:.5px;transition:transform .25s,box-shadow .25s,background .25s}
.btn-orange{background:var(--grad-orange);color:#fff;box-shadow:0 10px 28px rgba(255,138,30,.32);position:relative;overflow:hidden}
.btn-orange::after{content:"";position:absolute;top:0;left:-80%;width:50%;height:100%;background:linear-gradient(100deg,transparent,rgba(255,255,255,.45),transparent);transform:skewX(-20deg);transition:left .5s}
.btn-orange:hover::after{left:120%}
.btn-orange:hover{transform:translateY(-2px);box-shadow:0 16px 38px rgba(255,138,30,.45);color:#fff}
.btn-nav{height:48px;padding:0 28px;font-size:15px;border-radius:999px}
.btn-ghost{border:1.5px solid rgba(35,80,160,.3);color:var(--ink);background:#fff}
.btn-ghost:hover{border-color:var(--blue-2);background:rgba(14,165,233,.06);color:var(--blue)}
.hamburger{display:none;flex-direction:column;justify-content:center;gap:5px;width:44px;height:44px;border-radius:12px;border:1px solid rgba(255,255,255,.35);padding:0 10px;background:rgba(255,255,255,.08)}
.hamburger span{display:block;height:2px;border-radius:2px;background:#fff;transition:transform .3s,opacity .3s}
.hamburger.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.hamburger.open span:nth-child(2){opacity:0}
.hamburger.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* 移动抽屉（白底） */
.mobile-drawer{position:fixed;top:0;right:0;bottom:0;width:min(360px,88vw);background:#fff;z-index:960;transform:translateX(105%);transition:transform .38s cubic-bezier(.22,.8,.3,1);overflow-y:auto;padding:20px 20px 130px;border-left:1px solid var(--line);box-shadow:-18px 0 50px rgba(30,60,120,.16)}
.mobile-drawer.open{transform:translateX(0)}
.drawer-mask{position:fixed;inset:0;background:rgba(23,41,78,.4);backdrop-filter:blur(3px);z-index:950;opacity:0;visibility:hidden;transition:opacity .35s,visibility .35s}
.drawer-mask.show{opacity:1;visibility:visible}
.drawer-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px}
.drawer-top img{height:42px;background:#fff;border:1px solid var(--line);border-radius:10px;padding:4px 8px}
.drawer-close{width:40px;height:40px;border-radius:12px;border:1px solid var(--line);color:var(--ink-2);font-size:20px;line-height:1;background:#fff}
.drawer-badges{margin-bottom:16px}
.drawer-badges .cert-pre{display:block;margin-bottom:8px;color:var(--ink-2)}
.drawer-badges .cert-set{display:flex;flex-wrap:wrap;gap:8px}
.drawer-badges .cert-set img{height:26px}
.drawer-search{display:flex;gap:8px;margin-bottom:18px}
.drawer-search input{flex:1;height:44px;border-radius:12px;border:1px solid var(--line);background:var(--card-2);color:var(--ink);padding:0 14px;outline:none}
.drawer-search input::placeholder{color:var(--ink-3)}
.drawer-search button{width:52px;border-radius:12px;background:var(--grad-orange)}
.drawer-search button svg{width:19px;height:19px;fill:#fff}
.drawer-nav a{display:flex;align-items:center;justify-content:space-between;padding:13px 6px;border-bottom:1px solid rgba(35,80,160,.1);font-size:16px;font-weight:600;color:var(--ink-2)}
.drawer-nav a:hover{color:var(--blue)}
.drawer-nav .sub{display:none;padding:4px 0 10px}
.drawer-nav .sub a{border:0;padding:9px 12px;font-size:14px;font-weight:400;color:var(--ink-3)}
.drawer-nav li.open .sub{display:block}
.drawer-nav .arrow{transition:transform .3s}
.drawer-nav li.open .arrow{transform:rotate(180deg)}
.drawer-cta{margin-top:20px;display:flex;flex-direction:column;gap:10px}
.drawer-cta .btn{height:48px;width:100%}

/* 搜索浮层（白底） */
.search-layer{position:fixed;inset:0;z-index:980;background:rgba(244,247,252,.96);backdrop-filter:blur(18px);-webkit-backdrop-filter:blur(18px);display:flex;align-items:center;justify-content:center;opacity:0;visibility:hidden;transition:opacity .3s,visibility .3s}
.search-layer.show{opacity:1;visibility:visible}
.search-box{width:min(680px,88vw);text-align:center}
.search-box h3{font-size:20px;margin-bottom:22px;color:var(--ink-2);font-weight:600}
.search-box form{display:flex;gap:10px}
.search-box input{flex:1;height:58px;border-radius:16px;border:1.5px solid rgba(35,80,160,.28);background:#fff;color:var(--ink);font-size:17px;padding:0 20px;outline:none;box-shadow:0 10px 34px rgba(30,60,120,.08)}
.search-box input:focus{border-color:var(--blue-2)}
.search-box button{width:96px;border-radius:16px;background:var(--grad-orange);font-size:16px;font-weight:700;color:#fff}
.search-close{position:absolute;top:110px;right:40px;width:48px;height:48px;border-radius:50%;border:1px solid var(--line);color:var(--ink-2);font-size:22px;background:#fff}

/* ===== 响应式导航 ===== */
@media (max-width:1299px){
  .nav-item>a{font-size:13.5px;padding:0 11px}
  .nav-phone,.brand-side{display:none}
  .nav-inner{gap:12px}
}
@media (max-width:1023px){
  .nav-menu{display:none}
  .hamburger{display:flex}
  .nav-right .btn-nav{display:none}
  .nav-inner{justify-content:space-between}
}
@media (max-width:767px){
  :root{--nav-h:62px}
  .nav-inner{padding:0 14px}
  .brand-logo{height:40px;padding:4px 8px}
  .nav-right .icon-btn{display:none}
  .search-close{top:auto;bottom:38px;right:20px}
}
@media (min-width:1680px){
  .nav-item>a{font-size:17px;padding:0 22px}
}