/* ==========================================================================
   迈博建策 magbait.com · 主样式表 style.css
   设计语言：科技蓝（亮蓝）+ 浅冰蓝渐变背景 + 纯白
   布局：左侧垂直固定导航 + 右侧卡片流动（内页）
   ========================================================================== */

:root{
  --blue-primary:#2B7FFF;
  --blue-deep:#1A5BD6;
  --blue-light:#5B9DFF;
  --blue-ice:#E8F2FF;
  --blue-soft:#D4E6FF;
  --bg-white:#FFFFFF;
  --bg-ice:#F4F8FF;
  --bg-deep:#0D1B3D;
  --ink:#122040;
  --ink-soft:#4A5A80;
  --ink-mute:#8090B3;
  --line:rgba(43,127,255,.12);
  --line-strong:rgba(43,127,255,.25);
  --shadow:0 24px 60px -28px rgba(26,91,214,.35);
  --shadow-soft:0 14px 36px -20px rgba(26,91,214,.28);
  --radius:14px;
  --radius-sm:8px;
  --maxw:1240px;
  --nav-h:74px;
  --ease:cubic-bezier(.22,.61,.36,1);
  --sans:"Helvetica Neue",-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:var(--sans);
  font-size:15.5px;
  line-height:1.75;
  color:var(--ink);
  background:var(--bg-ice);
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto;display:block}
a{color:inherit;text-decoration:none;transition:color .25s var(--ease)}
ul,ol{list-style:none}
button{font-family:inherit;cursor:pointer;border:none;background:none}
input,textarea,select{font-family:inherit;font-size:inherit;color:inherit}

h1,h2,h3,h4,h5{font-weight:700;color:var(--ink);line-height:1.28;letter-spacing:.3px}
h1{font-size:clamp(2rem,4.6vw,3.4rem)}
h2{font-size:clamp(1.6rem,3.2vw,2.4rem)}
h3{font-size:clamp(1.25rem,2vw,1.6rem)}
h4{font-size:1.1rem}
p{color:var(--ink-soft)}
.accent{color:var(--blue-primary);font-weight:600}

.container{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 28px}
.section{position:relative;padding:96px 0}
.section.tight{padding:60px 0}
.section.narrow{padding:80px 0}
.bg-white{background:var(--bg-white)}
.bg-ice{background:var(--bg-ice)}
.bg-blue{background:linear-gradient(135deg,var(--blue-soft),var(--blue-ice));color:var(--ink)}
.bg-deep{background:var(--bg-deep);color:#fff}

/* ---------- 顶部固定导航栏 ---------- */
.topbar{
  position:fixed;top:0;left:0;right:0;z-index:1000;
  height:var(--nav-h);
  display:flex;align-items:center;
  transition:background .4s var(--ease),box-shadow .4s var(--ease),backdrop-filter .4s;
  background:rgba(255,255,255,.92);
  backdrop-filter:blur(14px);
  -webkit-backdrop-filter:blur(14px);
  border-bottom:1px solid var(--line);
}
.topbar.scrolled{
  background:rgba(255,255,255,.98);
  box-shadow:0 6px 30px -16px rgba(26,91,214,.25);
}
.topbar .nav-wrap{
  width:100%;max-width:var(--maxw);margin:0 auto;padding:0 24px;
  display:flex;align-items:center;justify-content:space-between;gap:18px;
}
.topbar .brand{display:flex;align-items:center;gap:10px;flex-shrink:0}
.topbar .brand img{height:38px;width:auto}
.nav-menu{display:flex;align-items:center;gap:1px;flex:1;justify-content:center}
.nav-menu > li{position:relative;flex-shrink:0}
.nav-menu > li > a{
  display:inline-flex;align-items:center;gap:4px;
  padding:10px 15px;font-size:14px;font-weight:500;color:var(--ink);white-space:nowrap;
  border-radius:var(--radius-sm);transition:all .25s var(--ease);
  position:relative;
}
.nav-menu > li > a .en{display:none}
.nav-menu > li > a:hover{color:var(--blue-primary);background:var(--blue-ice)}
.nav-menu > li > a.active{color:var(--blue-primary);font-weight:600}
.has-sub > a::after{
  content:"▾";
  display:inline-block;
  font-size:10px;line-height:1;
  margin-left:2px;opacity:.55;flex-shrink:0;
  transform:translateY(1px);
}
.sub-menu{
  position:absolute;top:calc(100% + 8px);left:50%;transform:translateX(-50%) translateY(8px);
  min-width:170px;background:#fff;border:1px solid var(--line);
  border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:8px;
  opacity:0;visibility:hidden;transition:all .28s var(--ease);
}
.has-sub:hover .sub-menu{opacity:1;visibility:visible;transform:translateX(-50%) translateY(0)}
.sub-menu a{display:block;padding:9px 14px;font-size:13px;color:var(--ink-soft);border-radius:var(--radius-sm);white-space:nowrap}
.sub-menu a:hover{background:var(--blue-ice);color:var(--blue-primary)}

.nav-cta{
  display:inline-flex;align-items:center;gap:6px;
  padding:9px 18px;font-size:13px;font-weight:600;color:#fff;white-space:nowrap;
  background:linear-gradient(135deg,var(--blue-primary),var(--blue-deep));
  border-radius:30px;transition:all .25s var(--ease);flex-shrink:0;
  box-shadow:0 4px 16px -4px rgba(43,127,255,.4);
}
.nav-cta:hover{transform:translateY(-1px);box-shadow:0 6px 20px -4px rgba(43,127,255,.5)}

.hamburger{display:none;width:42px;height:42px;position:relative}
.hamburger span{
  position:absolute;left:10px;right:10px;height:2px;background:var(--ink);
  border-radius:2px;transition:all .3s var(--ease);
}
.hamburger span:nth-child(1){top:14px}
.hamburger span:nth-child(2){top:20px}
.hamburger span:nth-child(3){top:26px}
.hamburger.open span:nth-child(1){top:20px;transform:rotate(45deg)}
.hamburger.open span:nth-child(2){opacity:0}
.hamburger.open span:nth-child(3){top:20px;transform:rotate(-45deg)}

.mobile-drawer{
  position:fixed;top:0;right:0;z-index:999;
  width:min(86vw,360px);height:100vh;background:#fff;
  transform:translateX(100%);transition:transform .4s var(--ease);
  display:flex;flex-direction:column;padding:calc(var(--nav-h) + 16px) 24px 24px;
  overflow-y:auto;box-shadow:-20px 0 60px -30px rgba(0,0,0,.3);
}
.mobile-drawer.open{transform:translateX(0)}
.mobile-drawer .m-nav{display:flex;flex-direction:column;gap:2px}
.mobile-drawer .m-nav > a,.mobile-drawer .m-nav .m-has-sub > .m-title{
  display:flex;justify-content:space-between;align-items:center;
  padding:14px 12px;font-size:15px;color:var(--ink);
  border-bottom:1px solid var(--line);cursor:pointer;
}
.mobile-drawer .m-nav .m-sub{display:none;flex-direction:column;padding-left:16px}
.mobile-drawer .m-nav .m-has-sub.open .m-sub{display:flex}
.mobile-drawer .m-nav .m-sub a{padding:10px 12px;font-size:13.5px;color:var(--ink-soft)}
.mobile-drawer .m-cta{margin-top:20px;text-align:center}
.mobile-drawer .m-contact{margin-top:auto;padding-top:20px;border-top:1px solid var(--line);font-size:13px;color:var(--ink-mute)}
.drawer-overlay{position:fixed;inset:0;z-index:998;background:rgba(13,27,61,.4);opacity:0;visibility:hidden;transition:all .3s}
.drawer-overlay.open{opacity:1;visibility:visible}

.sec-head{margin-bottom:48px;position:relative}
.sec-head.center{text-align:center;margin-left:auto;margin-right:auto;max-width:680px}
.sec-head .eyebrow{
  display:inline-flex;align-items:center;gap:8px;
  font-size:12px;font-weight:600;letter-spacing:3px;text-transform:uppercase;
  color:var(--blue-primary);margin-bottom:14px;
}
.sec-head .eyebrow::before{content:"";width:24px;height:2px;background:var(--blue-primary)}
.sec-head h2{margin-bottom:14px}
.sec-head p{font-size:15px;color:var(--ink-mute);max-width:60ch}
.sec-head.center p{margin-left:auto;margin-right:auto}

.reveal{opacity:0;transform:translateY(28px);transition:opacity .8s var(--ease),transform .8s var(--ease)}
.reveal.in{opacity:1;transform:none}
.reveal.d1{transition-delay:.1s}
.reveal.d2{transition-delay:.2s}
.reveal.d3{transition-delay:.3s}
.reveal.d4{transition-delay:.4s}

.back-top{
  position:fixed;right:24px;bottom:24px;z-index:900;
  width:46px;height:46px;border-radius:50%;
  background:linear-gradient(135deg,var(--blue-primary),var(--blue-deep));color:#fff;display:flex;align-items:center;justify-content:center;
  opacity:0;visibility:hidden;transform:translateY(12px);transition:all .3s var(--ease);
  box-shadow:var(--shadow-soft);
}
.back-top.show{opacity:1;visibility:visible;transform:none}
.back-top:hover{transform:translateY(-2px)}

.site-foot{background:var(--bg-deep);color:#fff;padding:72px 0 0;position:relative}
.foot-grid{display:grid;grid-template-columns:1.6fr 1fr 1fr 1.3fr;gap:40px;padding-bottom:48px}
.foot-col h4{color:#fff;margin-bottom:18px;font-size:15px;letter-spacing:1px}
.foot-col p{color:rgba(255,255,255,.55);font-size:13.5px;line-height:1.8}
.foot-brand{display:flex;align-items:center;gap:10px;margin-bottom:14px}
.foot-brand img{height:36px;width:auto;filter:brightness(0) invert(1)}
.foot-brand strong{color:#fff;font-size:17px}
.foot-col ul li{margin-bottom:10px}
.foot-col ul li a{font-size:13.5px;color:rgba(255,255,255,.6);transition:color .2s}
.foot-col ul li a:hover{color:var(--blue-light)}
.foot-contact li{display:flex;align-items:flex-start;gap:9px;color:rgba(255,255,255,.7);font-size:13.5px;margin-bottom:12px;line-height:1.6}
.foot-contact svg{flex-shrink:0;margin-top:3px;color:var(--blue-light)}
.foot-bottom{
  border-top:1px solid rgba(255,255,255,.1);padding:22px 0;
  display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;
}
.foot-bottom p{font-size:12.5px;color:rgba(255,255,255,.45)}
.foot-bottom .icp{color:var(--blue-light)}
.foot-links{display:flex;gap:18px}
.foot-links a{font-size:12.5px;color:rgba(255,255,255,.5)}
.foot-links a:hover{color:var(--blue-light)}

.breadcrumb{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--ink-mute);margin-bottom:32px;flex-wrap:wrap}
.breadcrumb a:hover{color:var(--blue-primary)}
.breadcrumb span{opacity:.5}
.breadcrumb .current{color:var(--ink)}

.page-hero{
  position:relative;padding:calc(var(--nav-h) + 64px) 0 56px;
  background:linear-gradient(135deg,var(--blue-ice),var(--bg-white));
  overflow:hidden;
}
.page-hero::before{
  content:"";position:absolute;top:30%;right:-8%;width:380px;height:380px;
  background:radial-gradient(circle,rgba(43,127,255,.1),transparent 70%);border-radius:50%;
}
.page-hero .eyebrow{
  display:inline-block;font-size:12px;font-weight:600;letter-spacing:3px;text-transform:uppercase;
  color:var(--blue-primary);margin-bottom:16px;
}
.page-hero h1{margin-bottom:14px}
.page-hero p{font-size:16px;color:var(--ink-soft);max-width:60ch}

@media (max-width:1150px){
  :root{--nav-h:64px}
  .nav-menu,.nav-cta{display:none}
  .hamburger{display:block}
}
@media (max-width:1080px){
  .foot-grid{grid-template-columns:1fr 1fr;gap:32px}
}
@media (max-width:880px){
  :root{--nav-h:62px}
  .section{padding:72px 0}
  .foot-grid{grid-template-columns:1fr;gap:28px}
  .foot-bottom{flex-direction:column;align-items:flex-start}
}
@media (max-width:560px){
  .container{padding:0 20px}
  body{font-size:14.5px}
  .section{padding:60px 0}
}