/* ===== 比特指纹浏览器 - 官网深色SaaS安全风 ===== */
:root {
  --bg: #050a14;
  --bg2: #0a1122;
  --bg3: #0f152d;
  --card: #0d1426;
  --card-hover: #141d33;
  --border: #1a2640;
  --border-light: #223358;
  --text: #e6ecf8;
  --text2: #9aafd0;
  --text3: #556888;
  --cyan: #00b4d8;
  --cyan-light: #33c4e0;
  --blue: #4361ee;
  --blue-light: #6678f3;
  --grad: linear-gradient(135deg, #4361ee, #00b4d8);
  --grad-soft: linear-gradient(135deg, rgba(67,97,238,0.06), rgba(0,180,216,0.06));
  --radius: 14px;
  --radius-sm: 8px;
  --shadow: 0 8px 32px rgba(0,0,0,0.5);
  --shadow-lg: 0 24px 64px rgba(0,0,0,0.7);
  --trans: 0.3s cubic-bezier(0.4,0,0.2,1);
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg);color:var(--text);line-height:1.65;
  -webkit-font-smoothing:antialiased;overflow-x:hidden;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}

/* 导航 - 深色科技毛玻璃 */
.nav-bar{
  position:fixed;top:0;left:0;right:0;z-index:1000;
  background:rgba(5,10,20,0.9);backdrop-filter:blur(24px);-webkit-backdrop-filter:blur(24px);
  border-bottom:1px solid rgba(26,38,64,0.6);
}
.nav-inner{
  max-width:1240px;margin:0 auto;padding:0 32px;height:66px;
  display:flex;align-items:center;justify-content:space-between;
}
.nav-brand{display:flex;align-items:center;gap:10px;font-size:17px;font-weight:800;letter-spacing:-0.3px}
.nav-brand img{width:30px;height:30px}
.nav-brand .accent{color:var(--cyan)}
.nav-menu{display:flex;align-items:center;gap:4px}
.nav-menu a{padding:9px 18px;border-radius:8px;font-size:14px;font-weight:500;color:var(--text2);transition:all var(--trans)}
.nav-menu a:hover{color:#fff;background:rgba(0,180,216,0.06)}
.nav-menu a.btn-nav{background:var(--grad);color:#fff;font-weight:700;border-radius:8px;padding:10px 22px;box-shadow:0 4px 18px rgba(67,97,238,0.35)}
.nav-menu a.btn-nav:hover{transform:translateY(-1px);box-shadow:0 6px 24px rgba(67,97,238,0.5)}
.nav-toggle{display:none;background:none;border:none;color:var(--text);font-size:24px;cursor:pointer}

/* Hero */
.hero{
  padding:148px 0 80px;position:relative;overflow:hidden;
  background:
    radial-gradient(ellipse 70% 50% at 40% 10%,rgba(67,97,238,0.08) 0%,transparent 55%),
    radial-gradient(ellipse 50% 40% at 80% 60%,rgba(0,180,216,0.04) 0%,transparent 50%);
}
.hero-grid{
  max-width:1240px;margin:0 auto;padding:0 32px;
  display:grid;grid-template-columns:1fr 1fr;gap:72px;align-items:center;
  position:relative;z-index:1
}
.hero-text .tag{
  display:inline-flex;align-items:center;gap:8px;
  padding:5px 16px;border-radius:6px;
  background:rgba(0,180,216,0.08);border:1px solid rgba(0,180,216,0.15);
  color:var(--cyan-light);font-size:12px;font-weight:700;letter-spacing:0.5px;margin-bottom:28px
}
.hero-text .tag::before{content:"";width:6px;height:6px;background:var(--cyan);border-radius:50%;animation:dot-pulse 2s infinite}
@keyframes dot-pulse{0%,100%{opacity:1;box-shadow:0 0 8px var(--cyan)}50%{opacity:0.3;box-shadow:0 0 16px var(--cyan)}}
.hero-text h1{font-size:clamp(36px,5vw,54px);font-weight:900;line-height:1.05;letter-spacing:-1px;margin-bottom:20px}
.hero-text h1 .hl{background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-text .desc{font-size:16px;color:var(--text3);line-height:1.8;margin-bottom:34px;max-width:460px}
.hero-btns{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.hero-btns .ver{font-size:12px;color:var(--text3);margin-left:8px}
.btn{display:inline-flex;align-items:center;gap:8px;padding:14px 28px;border-radius:8px;font-size:14px;font-weight:600;cursor:pointer;transition:all var(--trans);border:none;white-space:nowrap}
.btn-fill{background:var(--grad);color:#fff;box-shadow:0 8px 28px rgba(67,97,238,0.35)}
.btn-fill:hover{transform:translateY(-2px);box-shadow:0 14px 40px rgba(67,97,238,0.5)}
.btn-line{background:transparent;color:var(--text);border:1px solid var(--border-light)}
.btn-line:hover{border-color:var(--cyan);color:var(--cyan-light)}
.btn-muted{background:rgba(255,255,255,0.03);color:var(--text);border:1px solid var(--border)}
.btn-muted:hover{background:rgba(255,255,255,0.06)}
.btn-white{background:rgba(255,255,255,0.04);color:var(--text);border:1px solid var(--border)}
.btn-white:hover{background:rgba(255,255,255,0.08);border-color:var(--border-light)}

/* 面板mockup */
.vis-mock{position:relative}
.vis-window{
  background:var(--card);border:1px solid var(--border);
  border-radius:14px;overflow:hidden;box-shadow:var(--shadow-lg)
}
.vis-topbar{padding:12px 16px;background:var(--bg2);display:flex;align-items:center;gap:8px;border-bottom:1px solid var(--border)}
.vis-dot{width:10px;height:10px;border-radius:50%}
.vis-dot.r{background:#ff5f56}.vis-dot.y{background:#ffbd2e}.vis-dot.g{background:#27c93f}
.vis-tabs{display:flex;gap:2px;margin-left:12px}
.vis-tab{padding:4px 14px;border-radius:5px;font-size:10px;color:var(--text3);font-weight:500}
.vis-tab.active{background:rgba(67,97,238,0.15);color:var(--blue-light)}
.vis-body{padding:24px}
.vis-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}
.vis-item{padding:16px;border-radius:10px;border:1px solid var(--border);text-align:center}
.vis-item .vi-num{font-size:22px;font-weight:800;color:var(--cyan);margin-bottom:4px}
.vis-item .vi-label{font-size:10px;color:var(--text3)}
.vis-float{
  position:absolute;top:-20px;right:-16px;
  background:var(--card);border:1px solid var(--border);
  border-radius:10px;padding:12px 18px;box-shadow:var(--shadow);
  display:flex;align-items:center;gap:10px
}
.vis-float strong{color:var(--cyan-light);font-size:13px}

/* 平台条 */
.plat-strip{
  max-width:1240px;margin:0 auto;padding:0 32px 72px;position:relative;z-index:1
}
.plat-inner{
  background:var(--grad-soft);border:1px solid var(--border);
  border-radius:var(--radius);padding:24px 40px;
  display:flex;align-items:center;justify-content:center;gap:40px;flex-wrap:wrap
}
.plat-inner .pi{display:flex;align-items:center;gap:10px;font-size:13px;color:var(--text2);font-weight:500}

/* 区块 */
.sec{max-width:1240px;margin:0 auto;padding:80px 32px}
.sec-head{text-align:center;margin-bottom:56px}
.sec-head .label{
  display:inline-block;padding:5px 16px;border-radius:6px;
  background:rgba(0,180,216,0.08);border:1px solid rgba(0,180,216,0.15);
  color:var(--cyan-light);font-size:12px;font-weight:700;letter-spacing:1px;margin-bottom:16px
}
.sec-head h2{font-size:clamp(28px,4vw,40px);font-weight:800;letter-spacing:-0.5px;margin-bottom:12px}
.sec-head p{color:var(--text3);font-size:16px;max-width:520px;margin:0 auto}

/* 功能卡片 */
.feat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.feat-card{
  background:var(--card);border:1px solid var(--border);
  border-radius:var(--radius);padding:32px 26px;text-align:center;
  transition:all var(--trans);position:relative;overflow:hidden
}
.feat-card::before{
  content:"";position:absolute;top:0;left:50%;transform:translateX(-50%);
  width:0;height:2px;background:var(--grad);border-radius:0 0 2px 2px;
  transition:width var(--trans)
}
.feat-card:hover::before{width:80%}
.feat-card:hover{border-color:rgba(0,180,216,0.2);transform:translateY(-4px);box-shadow:0 16px 40px rgba(0,0,0,0.5)}
.feat-card .fc-icon{font-size:34px;margin-bottom:14px;display:block}
.feat-card h3{font-size:16px;font-weight:700;margin-bottom:8px}
.feat-card p{font-size:13px;color:var(--text3);line-height:1.7}

/* 扩展区 */
.dark-zone{
  background:linear-gradient(180deg,var(--bg),var(--bg2),var(--bg));
  border-top:1px solid var(--border);border-bottom:1px solid var(--border)
}
.extra-row{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.extra-card{
  background:var(--card);border:1px solid var(--border);
  border-radius:var(--radius);padding:36px 28px;text-align:center;
  transition:all var(--trans)
}
.extra-card:hover{border-color:var(--border-light);transform:translateY(-2px);box-shadow:var(--shadow)}
.extra-card .ei{font-size:40px;margin-bottom:12px;display:block}
.extra-card h3{font-size:16px;font-weight:700;margin-bottom:8px}
.extra-card p{font-size:13px;color:var(--text3);line-height:1.6}

/* 数据指标 */
.stat-row{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.stat-card{
  background:var(--card);border:1px solid var(--border);
  border-radius:var(--radius);padding:28px 20px;text-align:center
}
.stat-card .sn{font-size:38px;font-weight:900;background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.stat-card .sl{font-size:13px;color:var(--text2);margin-top:4px}

/* FAQ */
.faq-wrap{max-width:760px;margin:0 auto;display:flex;flex-direction:column;gap:10px}
.faq-item{background:var(--card);border:1px solid var(--border);border-radius:var(--radius-sm);overflow:hidden}
.faq-q{
  width:100%;padding:20px 24px;background:none;border:none;
  color:var(--text);font-size:15px;font-weight:600;text-align:left;
  cursor:pointer;display:flex;justify-content:space-between;align-items:center;
  font-family:inherit
}
.faq-q .arrow{font-size:11px;color:var(--cyan-light);transition:transform var(--trans)}
.faq-a{padding:0 24px 20px;font-size:14px;color:var(--text3);line-height:1.8;display:none}
.faq-item.open .faq-a{display:block}
.faq-item.open .arrow{transform:rotate(180deg)}

/* CTA */
.cta-box{
  background:var(--grad-soft);border:1px solid var(--border);
  border-radius:var(--radius);padding:64px 48px;text-align:center
}
.cta-box h2{font-size:clamp(28px,4vw,38px);font-weight:800;margin-bottom:12px}
.cta-box p{color:var(--text3);font-size:16px;margin-bottom:30px}
.cta-box .cta-btns{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}

/* Footer */
.footer{background:var(--bg2);border-top:1px solid var(--border)}
.footer-grid{
  max-width:1240px;margin:0 auto;padding:56px 32px 28px;
  display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:48px
}
.footer-brand .fl{display:flex;align-items:center;gap:10px;font-size:17px;font-weight:800;margin-bottom:12px}
.footer-brand .fl img{width:28px;height:28px}
.footer-brand .fl .fc{color:var(--cyan)}
.footer-brand p{font-size:13px;color:var(--text3);line-height:1.7;max-width:260px}
.footer-col h4{font-size:14px;font-weight:700;margin-bottom:16px}
.footer-col a{display:block;font-size:13px;color:var(--text3);padding:5px 0;transition:color var(--trans)}
.footer-col a:hover{color:var(--cyan)}
.footer-bottom{
  max-width:1240px;margin:0 auto;padding:18px 32px;
  border-top:1px solid var(--border);
  display:flex;justify-content:space-between;font-size:12px;color:var(--text3);
  flex-wrap:wrap;gap:12px
}

/* Download */
.dl-hero{padding:132px 0 60px;text-align:center;background:radial-gradient(ellipse 60% 50% at 50% 30%,rgba(67,97,238,0.05) 0%,transparent 55%)}
.dl-hero-inner{max-width:760px;margin:0 auto;padding:0 32px}
.dl-hero-inner h1{font-size:clamp(30px,5vw,46px);font-weight:900;margin-bottom:12px}
.dl-hero-inner .dl-sub{color:var(--text3);font-size:15px;margin-bottom:20px}
.dl-meta{display:inline-flex;gap:20px;font-size:13px;color:var(--text2);flex-wrap:wrap}
.dl-cards{max-width:1240px;margin:0 auto;padding:0 32px 60px}
.dl-single-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.dl-grid{max-width:1240px;margin:0 auto 60px;padding:0 32px;display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.dl-card{
  background:var(--card);border:1px solid var(--border);
  border-radius:var(--radius);padding:36px 28px;text-align:center;
  transition:all var(--trans);display:flex;flex-direction:column;align-items:center;gap:12px
}
.dl-card.primary{border-color:rgba(0,180,216,0.25)}
.dl-card:hover{border-color:var(--cyan);transform:translateY(-2px);box-shadow:var(--shadow)}
.dl-card .dl-os{display:inline-block;padding:4px 14px;border-radius:6px;font-size:12px;font-weight:700;background:rgba(0,180,216,0.08);color:var(--cyan-light)}
.dl-card .dl-tag{display:inline-block;padding:4px 14px;border-radius:6px;font-size:12px;font-weight:700;background:rgba(0,180,216,0.08);color:var(--cyan-light);align-self:center}
.dl-card h3{font-size:20px;font-weight:700}
.dl-card .dl-ver{font-size:13px;color:var(--text3)}
.dl-card .dl-info{font-size:13px;color:var(--text3);line-height:1.6}
.dl-card .dl-feats{display:flex;flex-wrap:wrap;gap:8px;justify-content:center}
.dl-card .dl-feats span{padding:5px 12px;border-radius:6px;background:rgba(67,97,238,0.08);font-size:12px;color:var(--text2)}
.dl-card .dl-size{font-size:12px;color:var(--text3)}
.dl-card .btn.primary,.dl-card .btn{width:100%;justify-content:center}
.dl-tips{max-width:1240px;margin:0 auto 60px;padding:0 32px;display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.dl-tips .tp{background:var(--card);border:1px solid var(--border);border-radius:var(--radius-sm);padding:24px 20px;display:flex;gap:14px;align-items:flex-start}
.tp .tp-num{width:30px;height:30px;border-radius:8px;background:rgba(0,180,216,0.08);color:var(--cyan-light);display:grid;place-items:center;font-size:14px;font-weight:800;flex-shrink:0}
.tp strong{display:block;font-size:14px;margin-bottom:4px}
.tp p{font-size:12px;color:var(--text3);line-height:1.6}

/* Download extras */
.dl-extra-section{max-width:1240px;margin:0 auto;padding:0 32px 80px}
.dl-extra-section .section-header{text-align:center;margin-bottom:48px}
.dl-extra-section .section-header .label{
  display:inline-block;padding:5px 16px;border-radius:6px;
  background:rgba(0,180,216,0.08);border:1px solid rgba(0,180,216,0.15);
  color:var(--cyan-light);font-size:12px;font-weight:700;letter-spacing:1px;margin-bottom:16px
}
.dl-extra-section .section-header h2{font-size:clamp(28px,4vw,40px);font-weight:800;margin-bottom:12px}
.dl-extra-section .section-header p{color:var(--text3);font-size:16px}
.dl-extra-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.dl-extra-card{
  background:var(--card);border:1px solid var(--border);
  border-radius:var(--radius);padding:36px 28px;text-align:center;
  transition:all var(--trans);display:flex;flex-direction:column;align-items:center;gap:12px
}
.dl-extra-card:hover{border-color:var(--border-light);transform:translateY(-2px);box-shadow:var(--shadow)}
.dl-extra-card .ex-icon{font-size:40px;margin-bottom:4px}
.dl-extra-card h4{font-size:16px;font-weight:700}
.dl-extra-card p{font-size:13px;color:var(--text3);line-height:1.6}

/* Specs section */
.section.sm{max-width:1240px;margin:0 auto;padding:0 32px 80px}
.section.sm .section-header{text-align:center;margin-bottom:48px}
.section.sm .section-header .label{
  display:inline-block;padding:5px 16px;border-radius:6px;
  background:rgba(0,180,216,0.08);border:1px solid rgba(0,180,216,0.15);
  color:var(--cyan-light);font-size:12px;font-weight:700;letter-spacing:1px;margin-bottom:16px
}
.section.sm .section-header h2{font-size:clamp(28px,4vw,40px);font-weight:800;margin-bottom:12px}
.specs-card{max-width:760px;margin:0 auto;background:var(--card);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}
.spec-row{display:grid;grid-template-columns:160px 1fr;border-bottom:1px solid var(--border)}
.spec-row:last-child{border-bottom:none}
.spec-label{padding:15px 20px;background:var(--bg3);font-size:13px;font-weight:700;color:var(--cyan-light)}
.spec-value{padding:15px 20px;font-size:13px;color:var(--text2)}

.specs-tbl{max-width:760px;margin:0 auto;background:var(--card);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}
.specs-tbl .sr{display:grid;grid-template-columns:160px 1fr;border-bottom:1px solid var(--border)}
.specs-tbl .sr:last-child{border-bottom:none}
.specs-tbl .sl{padding:15px 20px;background:var(--bg3);font-size:13px;font-weight:700;color:var(--cyan-light)}
.specs-tbl .sv{padding:15px 20px;font-size:13px;color:var(--text2)}

/* 404 */
.err-wrap{min-height:100vh;display:grid;place-items:center;padding:32px;background:var(--bg)}
.err-card{
  max-width:500px;text-align:center;
  background:var(--card);border:1px solid var(--border);
  border-radius:var(--radius);padding:60px 48px;box-shadow:var(--shadow-lg)
}
.err-card .err-num{font-size:clamp(90px,16vw,140px);font-weight:900;background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;line-height:0.9;margin-bottom:8px}
.err-card h1{font-size:21px;font-weight:700;margin-bottom:12px}
.err-card p{color:var(--text3);font-size:14px;line-height:1.7;margin-bottom:28px}
.err-card .err-btns{display:flex;gap:10px;justify-content:center;flex-wrap:wrap}

@media(max-width:1024px){
  .hero-grid{grid-template-columns:1fr;gap:44px}
  .feat-grid{grid-template-columns:repeat(2,1fr)}
  .extra-row{grid-template-columns:1fr;max-width:420px;margin:0 auto}
  .dl-single-grid,.dl-grid,.dl-extra-grid{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:768px){
  .nav-menu{display:none}
  .nav-toggle{display:block}
  .nav-menu.open{display:flex;flex-direction:column;position:absolute;top:66px;left:0;right:0;background:var(--bg2);border-bottom:1px solid var(--border);padding:12px 24px;gap:4px;z-index:99}
  .hero{padding:120px 0 50px}
  .feat-grid{grid-template-columns:1fr}
  .stat-row{grid-template-columns:repeat(2,1fr)}
  .dl-single-grid,.dl-grid,.dl-tips,.dl-extra-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr;gap:28px}
  .sec{padding:52px 20px}
  .cta-box{padding:44px 24px}
}