/* ============================================
   usdt下载入口在哪|可靠数字货币支付工具
   配色：深色(#0a0f1a)+比特币橙(#f7931a)+支付蓝(#2563eb)+合约金(#f59e0b)+安全绿(#10b981)+白
   ============================================ */
:root {
  --bg-primary: #0a0f1a;
  --bg-secondary: #111827;
  --bg-card: #1a1f2e;
  --bg-card-hover: #222839;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-btc: #f7931a;
  --accent-pay: #2563eb;
  --accent-gold: #f59e0b;
  --accent-green: #10b981;
  --accent-red: #ef4444;
  --border: #1e293b;
  --border-light: #334155;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow: 0 4px 20px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.5);
  --transition: all 0.3s ease;
  --max-width: 1200px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
}

a { color: var(--accent-pay); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--accent-btc); }

img { max-width: 100%; height: auto; display: block; }

/* ============================================
   Header & Navigation
   ============================================ */
header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(10,15,26,0.92); backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}

nav {
  max-width: var(--max-width); margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between; height: 64px;
}

.nav-brand {
  font-size: 1.4rem; font-weight: 700; color: var(--accent-btc);
  display: flex; align-items: center; gap: 8px;
}

.nav-brand span { color: var(--text-primary); }

.nav-links { display: flex; list-style: none; gap: 4px; }

.nav-links a {
  color: var(--text-secondary); padding: 8px 16px; border-radius: var(--radius);
  font-size: 0.95rem; font-weight: 500; transition: var(--transition);
}

.nav-links a:hover, .nav-links a.active {
  color: var(--text-primary); background: rgba(247,147,26,0.1);
}

.nav-cta {
  background: linear-gradient(135deg, var(--accent-btc), var(--accent-gold));
  color: #000 !important; padding: 10px 24px; border-radius: var(--radius);
  font-weight: 700; font-size: 0.95rem; transition: var(--transition);
}

.nav-cta:hover { transform: translateY(-2px); box-shadow: 0 4px 16px rgba(247,147,26,0.4); }

.menu-toggle { display: none; background: none; border: none; color: var(--text-primary); font-size: 1.5rem; cursor: pointer; }

/* ============================================
   Hero Section
   ============================================ */
.hero {
  padding: 140px 24px 100px; text-align: center;
  background: radial-gradient(ellipse at 50% 0%, rgba(247,147,26,0.08) 0%, transparent 60%),
              radial-gradient(ellipse at 80% 50%, rgba(37,99,235,0.06) 0%, transparent 50%);
  position: relative; overflow: hidden;
}

.hero::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M30 5 L35 25 L55 30 L35 35 L30 55 L25 35 L5 30 L25 25Z' fill='rgba(247,147,26,0.03)'/%3E%3C/svg%3E");
  opacity: 0.5;
}

.hero-content { position: relative; z-index: 1; max-width: 800px; margin: 0 auto; }

.hero-badge {
  display: inline-block; padding: 6px 20px; border-radius: 50px;
  background: rgba(247,147,26,0.1); border: 1px solid rgba(247,147,26,0.2);
  color: var(--accent-btc); font-size: 0.9rem; font-weight: 600; margin-bottom: 24px;
}

.hero h1 {
  font-size: 3.2rem; font-weight: 800; line-height: 1.3; margin-bottom: 20px;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-btc) 50%, var(--accent-gold) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}

.hero p {
  font-size: 1.2rem; color: var(--text-secondary); max-width: 650px; margin: 0 auto 32px;
}

.hero-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-flex; align-items: center; gap: 8px; padding: 14px 32px;
  border-radius: var(--radius); font-weight: 700; font-size: 1rem;
  border: none; cursor: pointer; transition: var(--transition); text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-btc), var(--accent-gold));
  color: #000; animation: pulse 2s infinite;
}

.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 8px 30px rgba(247,147,26,0.5); }

.btn-secondary {
  background: transparent; color: var(--text-primary);
  border: 2px solid var(--accent-pay);
}

.btn-secondary:hover { background: var(--accent-pay); color: #fff; transform: translateY(-3px); }

.btn-outline {
  background: transparent; color: var(--accent-green);
  border: 2px solid var(--accent-green);
}

.btn-outline:hover { background: var(--accent-green); color: #000; }

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(247,147,26,0.4); }
  50% { box-shadow: 0 0 0 16px rgba(247,147,26,0); }
}

/* Stats */
.hero-stats {
  display: flex; justify-content: center; gap: 48px; margin-top: 60px; flex-wrap: wrap;
}

.hero-stat { text-align: center; }
.hero-stat .num { font-size: 2.2rem; font-weight: 800; color: var(--accent-btc); }
.hero-stat .label { font-size: 0.9rem; color: var(--text-muted); margin-top: 4px; }

/* ============================================
   Sections
   ============================================ */
section { padding: 80px 24px; }

.section-header {
  text-align: center; margin-bottom: 56px;
}

.section-header h2 {
  font-size: 2.2rem; font-weight: 800; margin-bottom: 12px;
  color: var(--text-primary);
}

.section-header p { color: var(--text-secondary); font-size: 1.1rem; max-width: 600px; margin: 0 auto; }

.section-header .accent-line {
  width: 60px; height: 3px; background: var(--accent-btc);
  margin: 16px auto 0; border-radius: 2px;
}

/* ============================================
   Features Grid
   ============================================ */
.features-grid {
  max-width: var(--max-width); margin: 0 auto;
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}

.feature-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 32px; 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(--accent-btc), var(--accent-pay), var(--accent-gold));
  opacity: 0; transition: var(--transition);
}

.feature-card:hover::before { opacity: 1; }
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); border-color: var(--border-light); }

.feature-icon {
  width: 56px; height: 56px; border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem; margin-bottom: 20px;
}

.feature-card:nth-child(1) .feature-icon { background: rgba(37,99,235,0.15); color: var(--accent-pay); }
.feature-card:nth-child(2) .feature-icon { background: rgba(247,147,26,0.15); color: var(--accent-btc); }
.feature-card:nth-child(3) .feature-icon { background: rgba(245,158,11,0.15); color: var(--accent-gold); }
.feature-card:nth-child(4) .feature-icon { background: rgba(245,158,11,0.15); color: var(--accent-gold); }
.feature-card:nth-child(5) .feature-icon { background: rgba(37,99,235,0.15); color: var(--accent-pay); }
.feature-card:nth-child(6) .feature-icon { background: rgba(16,185,129,0.15); color: var(--accent-green); }

.feature-card h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 8px; }
.feature-card p { color: var(--text-secondary); font-size: 0.95rem; line-height: 1.6; }

/* ============================================
   Trading Assets Section
   ============================================ */
.assets { background: var(--bg-secondary); }

.assets-grid {
  max-width: var(--max-width); margin: 0 auto;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px;
}

.asset-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; text-align: center;
  transition: var(--transition);
}

.asset-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--accent-btc); }

.asset-card img { width: 48px; height: 48px; border-radius: 50%; margin: 0 auto 12px; }
.asset-card .asset-name { font-weight: 700; margin-bottom: 4px; }
.asset-card .asset-price { color: var(--accent-green); font-weight: 600; }
.asset-card .asset-change { font-size: 0.85rem; }
.asset-change.up { color: var(--accent-green); }
.asset-change.down { color: var(--accent-red); }

/* ============================================
   CTA Section
   ============================================ */
.cta {
  background: linear-gradient(135deg, rgba(247,147,26,0.1), rgba(37,99,235,0.1));
  text-align: center; position: relative; overflow: hidden;
}

.cta::before {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(ellipse at center, rgba(247,147,26,0.06) 0%, transparent 70%);
}

.cta-content { position: relative; z-index: 1; max-width: 700px; margin: 0 auto; }

.cta h2 { font-size: 2.2rem; font-weight: 800; margin-bottom: 16px; }
.cta p { color: var(--text-secondary); font-size: 1.1rem; margin-bottom: 32px; }

.cta-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ============================================
   Page Header (inner pages)
   ============================================ */
.page-header {
  padding: 120px 24px 60px; text-align: center;
  background: radial-gradient(ellipse at 50% 0%, rgba(247,147,26,0.06) 0%, transparent 60%);
}

.page-header h1 {
  font-size: 2.8rem; font-weight: 800; margin-bottom: 12px;
  background: linear-gradient(135deg, var(--text-primary), var(--accent-btc));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}

.page-header p { color: var(--text-secondary); font-size: 1.1rem; max-width: 600px; margin: 0 auto; }

/* ============================================
   Content sections
   ============================================ */
.content-section {
  max-width: var(--max-width); margin: 0 auto; padding: 0 24px 80px;
}

.content-section h2 {
  font-size: 1.8rem; font-weight: 700; margin-bottom: 24px;
  color: var(--text-primary); padding-bottom: 12px;
  border-bottom: 2px solid var(--border);
}

.content-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }

.content-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 28px; transition: var(--transition);
}

.content-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--accent-pay); }

.content-card h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 10px; color: var(--accent-btc); }
.content-card p { color: var(--text-secondary); font-size: 0.95rem; line-height: 1.7; }

/* Timeline */
.timeline { position: relative; padding-left: 32px; }
.timeline::before {
  content: ''; position: absolute; left: 8px; top: 0; bottom: 0;
  width: 2px; background: linear-gradient(180deg, var(--accent-btc), var(--accent-pay), var(--accent-green));
}

.timeline-item { position: relative; margin-bottom: 36px; }
.timeline-item::before {
  content: ''; position: absolute; left: -28px; top: 4px;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--accent-btc); border: 3px solid var(--bg-secondary);
}

.timeline-item .year { font-weight: 800; color: var(--accent-gold); margin-bottom: 4px; }
.timeline-item .desc { color: var(--text-secondary); font-size: 0.95rem; }

/* Team Grid */
.team-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.team-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 24px; text-align: center;
  transition: var(--transition);
}
.team-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.team-card img { width: 80px; height: 80px; border-radius: 50%; margin: 0 auto 16px; border: 3px solid var(--accent-btc); }
.team-card .team-name { font-weight: 700; margin-bottom: 4px; }
.team-card .team-role { color: var(--accent-pay); font-size: 0.9rem; }

/* ============================================
   Services Page
   ============================================ */
.services-list { display: flex; flex-direction: column; gap: 32px; }

.service-item {
  display: grid; grid-template-columns: 200px 1fr; gap: 32px;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 32px; transition: var(--transition);
}

.service-item:hover { border-color: var(--accent-btc); box-shadow: var(--shadow); }

.service-item img { width: 100%; height: 140px; object-fit: cover; border-radius: var(--radius); }

.service-item h3 { font-size: 1.25rem; font-weight: 700; margin-bottom: 10px; color: var(--accent-btc); }
.service-item p { color: var(--text-secondary); margin-bottom: 12px; }
.service-item .service-tags { display: flex; gap: 8px; flex-wrap: wrap; }
.service-tag {
  padding: 4px 12px; border-radius: 50px; font-size: 0.8rem;
  border: 1px solid var(--border-light); color: var(--text-muted);
}

/* ============================================
   FAQ Page
   ============================================ */
.faq-search {
  max-width: 600px; margin: 0 auto 40px; position: relative;
}

.faq-search input {
  width: 100%; padding: 14px 20px; border-radius: var(--radius);
  border: 1px solid var(--border-light); background: var(--bg-card);
  color: var(--text-primary); font-size: 1rem; outline: none;
}

.faq-search input:focus { border-color: var(--accent-pay); }

.faq-categories { display: flex; gap: 8px; justify-content: center; margin-bottom: 36px; flex-wrap: wrap; }

.faq-cat {
  padding: 8px 20px; border-radius: 50px; cursor: pointer;
  border: 1px solid var(--border-light); background: transparent;
  color: var(--text-secondary); font-size: 0.9rem; transition: var(--transition);
}

.faq-cat:hover, .faq-cat.active { background: rgba(247,147,26,0.1); border-color: var(--accent-btc); color: var(--accent-btc); }

.faq-group { margin-bottom: 40px; }
.faq-group h2 { font-size: 1.3rem; font-weight: 700; margin-bottom: 16px; color: var(--accent-btc); }

details {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); margin-bottom: 12px;
  transition: var(--transition);
}

details:hover { border-color: var(--border-light); }

summary {
  padding: 16px 20px; cursor: pointer; font-weight: 600;
  color: var(--text-primary); display: flex; align-items: center;
  justify-content: space-between; list-style: none;
}

summary::-webkit-details-marker { display: none; }
summary::after {
  content: '+'; font-size: 1.3rem; color: var(--accent-btc);
  font-weight: 700; transition: transform 0.3s;
}

details[open] summary::after { content: '−'; }

.faq-answer { padding: 0 20px 20px; color: var(--text-secondary); font-size: 0.95rem; line-height: 1.7; }

/* ============================================
   Contact Page
   ============================================ */
.contact-wrapper {
  display: grid; grid-template-columns: 1fr 1fr; gap: 40px;
}

.contact-form { display: flex; flex-direction: column; gap: 20px; }

.form-group label {
  display: block; margin-bottom: 6px; font-weight: 600; font-size: 0.9rem;
  color: var(--text-secondary);
}

.form-group input, .form-group select, .form-group textarea {
  width: 100%; padding: 12px 16px; border-radius: var(--radius);
  border: 1px solid var(--border-light); background: var(--bg-card);
  color: var(--text-primary); font-size: 0.95rem; outline: none;
  transition: var(--transition);
}

.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  border-color: var(--accent-btc);
}

.form-group textarea { resize: vertical; min-height: 120px; }

.contact-info { display: flex; flex-direction: column; gap: 24px; }

.contact-method {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; transition: var(--transition);
}

.contact-method:hover { border-color: var(--accent-pay); }
.contact-method .method-title { font-weight: 700; margin-bottom: 6px; display: flex; align-items: center; gap: 8px; }
.contact-method .method-title .icon { font-size: 1.2rem; }
.contact-method p { color: var(--text-secondary); font-size: 0.9rem; }

.social-links { display: flex; gap: 12px; flex-wrap: wrap; }
.social-link {
  padding: 10px 20px; border-radius: var(--radius); border: 1px solid var(--border-light);
  color: var(--text-secondary); font-size: 0.9rem; transition: var(--transition);
}
.social-link:hover { border-color: var(--accent-pay); color: var(--accent-pay); background: rgba(37,99,235,0.05); }

/* ============================================
   Table styles
   ============================================ */
.compare-table {
  width: 100%; border-collapse: collapse; margin-top: 24px;
}

.compare-table th, .compare-table td {
  padding: 14px 16px; text-align: left; border: 1px solid var(--border); font-size: 0.95rem;
}

.compare-table th {
  background: var(--bg-card); color: var(--accent-btc); font-weight: 700;
}

.compare-table td { color: var(--text-secondary); }

.compare-table tr:hover td { background: rgba(247,147,26,0.03); }

/* ============================================
   Footer
   ============================================ */
footer {
  background: var(--bg-secondary); border-top: 1px solid var(--border);
  padding: 48px 24px 24px; text-align: center;
}

.footer-grid {
  max-width: var(--max-width); margin: 0 auto 32px;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px;
  text-align: left;
}

.footer-col h4 { font-weight: 700; margin-bottom: 16px; color: var(--text-primary); }
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 8px; }
.footer-col ul li a { color: var(--text-muted); font-size: 0.9rem; }
.footer-col ul li a:hover { color: var(--accent-btc); }

.footer-bottom {
  border-top: 1px solid var(--border); padding-top: 20px;
  color: var(--text-muted); font-size: 0.9rem;
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInLeft {
  from { opacity: 0; transform: translateX(-30px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes fadeInRight {
  from { opacity: 0; transform: translateX(30px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes tickerScroll {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

@keyframes floatAnimation {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.reveal { opacity: 0; transform: translateY(30px); transition: all 0.6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

.reveal-left { opacity: 0; transform: translateX(-30px); transition: all 0.6s ease; }
.reveal-left.visible { opacity: 1; transform: translateX(0); }

.reveal-right { opacity: 0; transform: translateX(30px); transition: all 0.6s ease; }
.reveal-right.visible { opacity: 1; transform: translateX(0); }

/* Ticker */
.ticker-wrap {
  background: var(--bg-secondary); border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border); overflow: hidden; padding: 12px 0;
}

.ticker {
  display: flex; animation: tickerScroll 30s linear infinite; width: max-content;
}

.ticker-item {
  display: flex; align-items: center; gap: 8px; padding: 0 24px;
  white-space: nowrap; font-size: 0.9rem;
}

.ticker-item .pair { font-weight: 700; }
.ticker-item .price { color: var(--accent-green); }
.ticker-item .change-up { color: var(--accent-green); }
.ticker-item .change-down { color: var(--accent-red); }

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .assets-grid { grid-template-columns: repeat(2, 1fr); }
  .service-item { grid-template-columns: 1fr; }
  .team-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .hero p { font-size: 1rem; }
  .hero-stats { gap: 24px; }
  .hero-stat .num { font-size: 1.5rem; }

  .features-grid { grid-template-columns: 1fr; }
  .assets-grid { grid-template-columns: 1fr 1fr; }
  .content-grid { grid-template-columns: 1fr; }
  .team-grid { grid-template-columns: 1fr 1fr; }
  .contact-wrapper { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }

  .nav-links { display: none; position: fixed; top: 64px; left: 0; right: 0;
    background: var(--bg-primary); flex-direction: column; padding: 16px;
    border-bottom: 1px solid var(--border);
  }
  .nav-links.active { display: flex; }
  .menu-toggle { display: block; }

  .page-header h1 { font-size: 2rem; }
  .section-header h2 { font-size: 1.6rem; }
}

/* ============================================
   Breadcrumb
   ============================================ */
.breadcrumb {
  max-width: var(--max-width); margin: 0 auto 32px; padding: 0 24px;
  font-size: 0.9rem; color: var(--text-muted);
}

.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--accent-btc); }
.breadcrumb span { color: var(--accent-btc); }

/* ============================================
   Security badges
   ============================================ */
.security-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }

.security-badge {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 28px; text-align: center;
  transition: var(--transition);
}

.security-badge:hover { border-color: var(--accent-green); transform: translateY(-4px); }
.security-badge .badge-icon { font-size: 2rem; margin-bottom: 12px; color: var(--accent-green); }
.security-badge h4 { font-weight: 700; margin-bottom: 8px; }
.security-badge p { color: var(--text-secondary); font-size: 0.9rem; }

/* Print */
@media print {
  header, footer, .cta, .btn { display: none; }
  body { color: #000; background: #fff; }
}