/* === Reset & Base === */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;background:#0a0f1a;color:#e2e8f0;line-height:1.7;overflow-x:hidden}

/* === Color Variables === */
:root{
  --bg-primary:#0a0f1a;--bg-secondary:#111827;--bg-card:#1a2332;--bg-card-hover:#1f2d3d;
  --usdt-green:#26a17b;--usdt-green-light:#2ecc9e;--btc-orange:#f7931a;--btc-orange-light:#fba94c;
  --compat-blue:#2563eb;--compat-blue-light:#3b82f6;--trade-gold:#f59e0b;--trade-gold-light:#fbbf24;
  --text-primary:#f1f5f9;--text-secondary:#94a3b8;--text-muted:#64748b;
  --border-color:#1e293b;--shadow-md:0 4px 20px rgba(0,0,0,0.3);--shadow-lg:0 12px 40px rgba(0,0,0,0.5);
  --radius-sm:8px;--radius-md:12px;--radius-lg:20px;--radius-xl:28px;
  --transition:all 0.3s cubic-bezier(0.4,0,0.2,1)
}
.container{max-width:1200px;margin:0 auto;padding:0 24px}

/* === Header & Nav === */
header{position:sticky;top:0;z-index:1000;background:rgba(10,15,26,0.92);backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);border-bottom:1px solid var(--border-color)}
header .container{display:flex;align-items:center;justify-content:space-between;padding-top:16px;padding-bottom:16px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none}
.logo-icon{width:40px;height:40px;border-radius:10px;background:linear-gradient(135deg,var(--usdt-green),var(--compat-blue));display:flex;align-items:center;justify-content:center;font-size:18px;font-weight:800;color:#fff}
.logo-text{font-size:22px;font-weight:700;color:var(--text-primary);letter-spacing:-0.5px}
.logo-text span{color:var(--usdt-green)}
nav ul{display:flex;list-style:none;gap:8px}
nav a{display:block;padding:10px 18px;color:var(--text-secondary);text-decoration:none;border-radius:var(--radius-sm);font-size:15px;font-weight:500;transition:var(--transition);position:relative}
nav a:hover,nav a.active{color:var(--usdt-green-light);background:rgba(38,161,123,0.08)}
nav a.active::after{content:'';position:absolute;bottom:4px;left:50%;transform:translateX(-50%);width:20px;height:2px;background:var(--usdt-green);border-radius:2px}
.menu-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:8px;background:none;border:none}
.menu-toggle span{display:block;width:26px;height:2px;background:var(--text-primary);border-radius:2px;transition:var(--transition)}

/* === Hero === */
#hero{padding:100px 0 80px;position:relative;overflow:hidden}
#hero::before{content:'';position:absolute;top:-200px;right:-200px;width:600px;height:600px;background:radial-gradient(circle,rgba(38,161,123,0.08),transparent 70%);border-radius:50%;pointer-events:none}
#hero::after{content:'';position:absolute;bottom:-150px;left:-150px;width:500px;height:500px;background:radial-gradient(circle,rgba(37,99,235,0.06),transparent 70%);border-radius:50%;pointer-events:none}
.hero-grid{display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center;position:relative;z-index:1}
.hero-tag{display:inline-block;padding:6px 16px;background:rgba(38,161,123,0.12);border:1px solid rgba(38,161,123,0.25);border-radius:20px;color:var(--usdt-green-light);font-size:13px;font-weight:600;margin-bottom:20px;letter-spacing:0.5px}
h1{font-size:48px;font-weight:800;line-height:1.2;color:var(--text-primary);margin-bottom:20px;letter-spacing:-1px}
h1 .gradient-text{background:linear-gradient(135deg,var(--usdt-green-light),var(--compat-blue-light));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-subtitle{font-size:18px;color:var(--text-secondary);margin-bottom:32px;line-height:1.8;max-width:520px}
.hero-cta-group{display:flex;gap:16px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;gap:8px;padding:14px 32px;border-radius:var(--radius-lg);font-size:16px;font-weight:600;text-decoration:none;transition:var(--transition);cursor:pointer;border:none}
.btn-primary{background:linear-gradient(135deg,var(--usdt-green),var(--usdt-green-light));color:#fff;box-shadow:0 4px 20px rgba(38,161,123,0.35);position:relative;overflow:hidden}
.btn-primary::after{content:'';position:absolute;top:0;left:-100%;width:100%;height:100%;background:linear-gradient(90deg,transparent,rgba(255,255,255,0.2),transparent);animation:btnShine 2.5s infinite}
@keyframes btnShine{100%{left:100%}}
.btn-primary:hover{transform:translateY(-3px);box-shadow:0 8px 30px rgba(38,161,123,0.5)}
.btn-secondary{background:transparent;color:var(--text-primary);border:2px solid var(--border-color)}
.btn-secondary:hover{background:var(--bg-card);border-color:var(--usdt-green);color:var(--usdt-green-light);transform:translateY(-3px)}
.hero-visual{display:flex;justify-content:center;align-items:center}
.hero-visual img{border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);max-width:100%}

/* === Stats === */
#stats{padding:60px 0;border-top:1px solid var(--border-color);border-bottom:1px solid var(--border-color)}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:30px;text-align:center}
.stat-item{padding:24px}
.stat-number{font-size:42px;font-weight:800;background:linear-gradient(135deg,var(--usdt-green-light),var(--btc-orange-light));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.stat-label{font-size:14px;color:var(--text-muted);margin-top:6px}

/* === Section Common === */
section{padding:80px 0}
.section-header{text-align:center;margin-bottom:56px}
.section-header h2{font-size:36px;font-weight:700;color:var(--text-primary);margin-bottom:16px}
.section-header h2 .accent{color:var(--usdt-green)}
.section-header p{font-size:17px;color:var(--text-secondary);max-width:640px;margin:0 auto}

/* === Features === */
#features{position:relative}
.features-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.feature-card{background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:36px 28px;transition:var(--transition);position:relative;overflow:hidden}
.feature-card::before{content:'';position:absolute;top:0;left:0;right:0;height:3px;background:linear-gradient(90deg,var(--usdt-green),var(--compat-blue),var(--btc-orange));transform:scaleX(0);transition:transform 0.4s ease}
.feature-card:hover::before{transform:scaleX(1)}
.feature-card:hover{transform:translateY(-8px);box-shadow:var(--shadow-lg);border-color:rgba(38,161,123,0.3);background:var(--bg-card-hover)}
.feature-icon{width:56px;height:56px;border-radius:var(--radius-md);display:flex;align-items:center;justify-content:center;font-size:26px;margin-bottom:20px}
.feature-icon.green{background:rgba(38,161,123,0.15);color:var(--usdt-green-light)}
.feature-icon.orange{background:rgba(247,147,26,0.15);color:var(--btc-orange-light)}
.feature-icon.blue{background:rgba(37,99,235,0.15);color:var(--compat-blue-light)}
.feature-icon.gold{background:rgba(245,158,11,0.15);color:var(--trade-gold-light)}
.feature-card h3{font-size:20px;color:var(--text-primary);margin-bottom:12px}
.feature-card p{font-size:15px;color:var(--text-secondary);line-height:1.7}

/* === Brands Compatibility */
#compatibility{padding:80px 0;background:var(--bg-secondary)}
.brands-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.brand-card{background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:40px 24px;text-align:center;transition:var(--transition);cursor:default}
.brand-card:hover{transform:translateY(-6px);border-color:var(--compat-blue);box-shadow:0 8px 30px rgba(37,99,235,0.2)}
.brand-icon{font-size:48px;margin-bottom:16px}
.brand-card h3{font-size:18px;color:var(--text-primary);margin-bottom:8px}
.brand-card p{font-size:13px;color:var(--text-muted)}
.brand-check{display:inline-flex;align-items:center;gap:4px;padding:4px 12px;background:rgba(38,161,123,0.12);border-radius:12px;color:var(--usdt-green-light);font-size:12px;font-weight:600;margin-top:12px}

/* === Services === */
.services-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.service-card{background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:32px 24px;transition:var(--transition)}
.service-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-lg);border-color:var(--trade-gold)}
.service-icon{font-size:36px;margin-bottom:16px}
.service-card h3{font-size:20px;color:var(--text-primary);margin-bottom:10px}
.service-card ul{list-style:none;padding:0}
.service-card li{font-size:14px;color:var(--text-secondary);padding:6px 0;border-bottom:1px solid var(--border-color);position:relative;padding-left:18px}
.service-card li::before{content:'>';position:absolute;left:0;color:var(--usdt-green);font-weight:700}

/* === CTA === */
#cta{padding:100px 0;text-align:center;position:relative;overflow:hidden}
#cta::before{content:'';position:absolute;inset:0;background:radial-gradient(ellipse at center,rgba(38,161,123,0.08),transparent 70%);pointer-events:none}
#cta h2{font-size:40px;font-weight:800;color:var(--text-primary);margin-bottom:20px}
#cta p{font-size:18px;color:var(--text-secondary);margin-bottom:36px;max-width:600px;margin-left:auto;margin-right:auto}
.btn-cta{font-size:18px;padding:18px 48px;border-radius:var(--radius-xl);animation:pulse 2s infinite}
@keyframes pulse{0%,100%{box-shadow:0 0 0 0 rgba(38,161,123,0.4)}50%{box-shadow:0 0 0 20px rgba(38,161,123,0)}}
.btn-download{display:inline-flex;align-items:center;gap:10px;padding:16px 36px;background:linear-gradient(135deg,var(--btc-orange),var(--trade-gold));color:#000;border-radius:var(--radius-lg);font-size:16px;font-weight:700;text-decoration:none;transition:var(--transition);box-shadow:0 4px 20px rgba(247,147,26,0.35);animation:breathe 2.5s ease-in-out infinite}
@keyframes breathe{0%,100%{transform:scale(1)}50%{transform:scale(1.04)}}
.btn-download:hover{transform:translateY(-3px);box-shadow:0 8px 30px rgba(247,147,26,0.5)}

/* === About Page === */
.about-hero{text-align:center;padding:60px 0 40px}
.about-content{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:center;padding:40px 0}
.about-content img{border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);width:100%}
.about-text h2{font-size:28px;color:var(--text-primary);margin-bottom:16px}
.about-text p{font-size:16px;color:var(--text-secondary);line-height:1.9;margin-bottom:16px}
.timeline{position:relative;padding:40px 0}
.timeline::before{content:'';position:absolute;left:50%;top:0;bottom:0;width:2px;background:var(--border-color)}
.timeline-item{display:flex;align-items:flex-start;gap:32px;margin-bottom:32px;position:relative}
.timeline-item:nth-child(even){flex-direction:row-reverse}
.timeline-dot{width:16px;height:16px;background:var(--usdt-green);border-radius:50%;flex-shrink:0;margin-top:4px;box-shadow:0 0 0 4px rgba(38,161,123,0.2);z-index:1}
.timeline-content{flex:1;background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-md);padding:24px}
.timeline-year{font-size:14px;color:var(--usdt-green-light);font-weight:600;margin-bottom:6px}
.timeline-content h3{font-size:18px;color:var(--text-primary);margin-bottom:6px}
.timeline-content p{font-size:14px;color:var(--text-secondary)}
.team-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;padding:40px 0}
.team-card{background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:28px 20px;text-align:center;transition:var(--transition)}
.team-card:hover{transform:translateY(-5px);box-shadow:var(--shadow-md);border-color:var(--compat-blue)}
.team-card img{width:100px;height:100px;border-radius:50%;object-fit:cover;margin-bottom:16px;border:3px solid var(--compat-blue)}
.team-card h4{font-size:17px;color:var(--text-primary);margin-bottom:4px}
.team-card .role{font-size:13px;color:var(--usdt-green);font-weight:600;margin-bottom:8px}

/* === FAQ === */
.faq-list{max-width:800px;margin:0 auto}
details{margin-bottom:12px;background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-md);overflow:hidden;transition:var(--transition)}
details[open]{border-color:var(--usdt-green);box-shadow:0 0 0 1px rgba(38,161,123,0.15)}
summary{padding:20px 28px;font-size:17px;font-weight:600;color:var(--text-primary);cursor:pointer;list-style:none;display:flex;justify-content:space-between;align-items:center}
summary::-webkit-details-marker{display:none}
summary::after{content:'+';font-size:22px;font-weight:300;color:var(--usdt-green);transition:transform 0.3s}
details[open] summary::after{content:'-';transform:rotate(180deg)}
details .answer{padding:0 28px 24px;font-size:15px;color:var(--text-secondary);line-height:1.8}
.faq-category{margin-bottom:40px}
.faq-category h3{font-size:22px;color:var(--usdt-green-light);margin-bottom:20px;padding-bottom:10px;border-bottom:2px solid var(--border-color)}

/* === Contact === */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:48px}
.contact-form{background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:40px}
.form-group{margin-bottom:20px}
.form-group label{display:block;font-size:14px;font-weight:600;color:var(--text-primary);margin-bottom:8px}
.form-group input,.form-group textarea,.form-group select{width:100%;padding:14px 16px;background:var(--bg-primary);border:1px solid var(--border-color);border-radius:var(--radius-sm);color:var(--text-primary);font-size:15px;font-family:inherit;transition:var(--transition)}
.form-group input:focus,.form-group textarea:focus,.form-group select:focus{outline:none;border-color:var(--usdt-green);box-shadow:0 0 0 3px rgba(38,161,123,0.12)}
.form-group textarea{min-height:140px;resize:vertical}
.contact-info-card{background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:36px}
.contact-info-card h3{font-size:22px;color:var(--text-primary);margin-bottom:24px}
.contact-info-item{display:flex;align-items:flex-start;gap:14px;margin-bottom:20px;padding-bottom:20px;border-bottom:1px solid var(--border-color)}
.contact-info-item:last-child{border-bottom:none}
.contact-info-icon{font-size:24px;flex-shrink:0}
.contact-info-item strong{display:block;color:var(--text-primary);font-size:15px;margin-bottom:4px}
.contact-info-item span{font-size:14px;color:var(--text-muted)}
.social-links{display:flex;gap:12px;margin-top:20px}
.social-link{display:inline-flex;align-items:center;justify-content:center;width:44px;height:44px;background:var(--bg-primary);border:1px solid var(--border-color);border-radius:50%;text-decoration:none;font-size:20px;transition:var(--transition)}
.social-link:hover{background:var(--usdt-green);border-color:var(--usdt-green);transform:translateY(-3px)}

/* === Footer === */
footer{padding:48px 0;border-top:1px solid var(--border-color);text-align:center;background:var(--bg-secondary)}
footer .copyright{font-size:14px;color:var(--text-muted)}
footer .footer-links{display:flex;justify-content:center;gap:24px;margin-bottom:20px}
footer .footer-links a{color:var(--text-secondary);text-decoration:none;font-size:14px;transition:var(--transition)}
footer .footer-links a:hover{color:var(--usdt-green-light)}

/* === Animations === */
@keyframes fadeInUp{from{opacity:0;transform:translateY(30px)}to{opacity:1;transform:translateY(0)}}
.fade-in-up{animation:fadeInUp 0.6s ease forwards}
.reveal{opacity:0;transform:translateY(30px);transition:opacity 0.6s ease,transform 0.6s ease}
.reveal.visible{opacity:1;transform:translateY(0)}
.delay-1{animation-delay:0.1s}.delay-2{animation-delay:0.2s}.delay-3{animation-delay:0.3s}.delay-4{animation-delay:0.4s}.delay-5{animation-delay:0.5s}.delay-6{animation-delay:0.6s}

/* === Brand Switch Animation === */
@keyframes brandSwitch{0%,20%{opacity:1;transform:scale(1)}25%,45%{opacity:0;transform:scale(0.95)}50%,70%{opacity:0}75%,95%{opacity:1;transform:scale(1)}}
.brand-switch{animation:brandSwitch 6s infinite}

/* === Responsive === */
@media(max-width:1024px){
  .hero-grid{grid-template-columns:1fr;text-align:center}
  .hero-subtitle{margin-left:auto;margin-right:auto}
  .hero-cta-group{justify-content:center}
  .hero-visual{display:none}
  .features-grid{grid-template-columns:repeat(2,1fr)}
  .brands-grid{grid-template-columns:repeat(2,1fr)}
  .services-grid{grid-template-columns:repeat(2,1fr)}
  .stats-grid{grid-template-columns:repeat(2,1fr)}
  .about-content{grid-template-columns:1fr}
  .team-grid{grid-template-columns:repeat(2,1fr)}
  .contact-grid{grid-template-columns:1fr}
  .timeline::before{left:20px}
  .timeline-item,.timeline-item:nth-child(even){flex-direction:row}
}
@media(max-width:768px){
  h1{font-size:34px}
  .section-header h2{font-size:28px}
  .features-grid{grid-template-columns:1fr}
  .brands-grid{grid-template-columns:1fr}
  .services-grid{grid-template-columns:1fr}
  .stats-grid{grid-template-columns:1fr 1fr}
  .team-grid{grid-template-columns:1fr 1fr}
  nav ul{display:none;position:absolute;top:100%;left:0;right:0;background:var(--bg-secondary);flex-direction:column;padding:16px;border-bottom:1px solid var(--border-color)}
  nav ul.active{display:flex}
  .menu-toggle{display:flex}
  .hero-cta-group{flex-direction:column;align-items:center}
  section{padding:50px 0}
}
@media(max-width:480px){
  h1{font-size:28px}
  .stat-number{font-size:28px}
  .stats-grid{grid-template-columns:1fr}
  .team-grid{grid-template-columns:1fr}
  .container{padding:0 16px}
}