/* biubiu加速器 落地页样式 */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #00d4ff;
  --primary-dark: #0099cc;
  --accent: #0066ff;
  --bg-dark: #0a0e17;
  --bg-card: #111827;
  --bg-card-hover: #1a2332;
  --text: #e8edf5;
  --text-muted: #8899aa;
  --gradient: linear-gradient(135deg, #00d4ff 0%, #0066ff 100%);
  --shadow-glow: 0 0 30px rgba(0, 212, 255, 0.4);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  background: var(--bg-dark);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

a { color: var(--primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: #fff; }

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

.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(10, 14, 23, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(0, 212, 255, 0.1);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo img { height: 36px; width: auto; }

.nav-links { display: flex; gap: 28px; list-style: none; }
.nav-links a { color: var(--text-muted); font-size: 15px; }
.nav-links a:hover, .nav-links a.active { color: var(--primary); }

.header-cta .btn-download-sm {
  padding: 8px 20px;
  font-size: 14px;
}

/* Download Button - 吸引眼球 */
.btn-download {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 16px 40px;
  background: var(--gradient);
  color: #fff !important;
  font-size: 18px;
  font-weight: 700;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  text-decoration: none;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-glow);
  animation: pulse-glow 2s ease-in-out infinite;
  transition: transform 0.2s, box-shadow 0.2s;
}

.btn-download::before {
  content: '';
  position: absolute;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: linear-gradient(45deg, transparent 30%, rgba(255,255,255,0.15) 50%, transparent 70%);
  animation: shimmer 3s infinite;
}

.btn-download:hover {
  transform: translateY(-3px) scale(1.03);
  box-shadow: 0 0 50px rgba(0, 212, 255, 0.6);
  color: #fff !important;
}

.btn-download:active { transform: translateY(0) scale(0.98); }

.btn-download-sm { padding: 10px 24px; font-size: 14px; animation: none; }
.btn-download-sm::before { display: none; }

.btn-download-lg { padding: 20px 56px; font-size: 22px; }

.btn-download .icon { font-size: 1.2em; }

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 20px rgba(0, 212, 255, 0.3); }
  50% { box-shadow: 0 0 40px rgba(0, 212, 255, 0.6); }
}

@keyframes shimmer {
  0% { transform: translateX(-100%) rotate(45deg); }
  100% { transform: translateX(100%) rotate(45deg); }
}

/* Hero */
.hero {
  padding: 120px 0 80px;
  background: radial-gradient(ellipse at 50% 0%, rgba(0, 102, 255, 0.15) 0%, transparent 60%);
  text-align: center;
}

.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  background: rgba(0, 212, 255, 0.1);
  border: 1px solid rgba(0, 212, 255, 0.3);
  border-radius: 20px;
  font-size: 13px;
  color: var(--primary);
  margin-bottom: 24px;
}

.hero h1 {
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 16px;
  background: linear-gradient(135deg, #fff 0%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(16px, 2.5vw, 20px);
  color: var(--text-muted);
  max-width: 700px;
  margin: 0 auto 36px;
}

.hero-cta { margin-bottom: 48px; }

.hero-platforms {
  display: flex;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
}

.platform-item {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-size: 14px;
}

.platform-item img { width: 24px; height: 24px; object-fit: contain; }

/* Section */
.section { padding: 80px 0; }
.section-alt { background: rgba(17, 24, 39, 0.5); }

.section-header { text-align: center; margin-bottom: 48px; }

.section-header h2 {
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 700;
  margin-bottom: 12px;
}

.section-header p { color: var(--text-muted); font-size: 16px; max-width: 600px; margin: 0 auto; }

/* Feature Cards */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid rgba(0, 212, 255, 0.08);
  transition: transform 0.3s, border-color 0.3s;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(0, 212, 255, 0.25);
}

.feature-card img { width: 100%; aspect-ratio: 16/9; object-fit: cover; }

.feature-card-body { padding: 24px; }
.feature-card-body h3 { font-size: 18px; margin-bottom: 8px; color: var(--primary); }
.feature-card-body p { color: var(--text-muted); font-size: 14px; }

/* Stats */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 24px;
  text-align: center;
}

.stat-item h3 {
  font-size: 36px;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 4px;
}

.stat-item p { color: var(--text-muted); font-size: 14px; }

/* Tech Tags */
.tech-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 32px;
}

.tech-tag {
  padding: 8px 20px;
  background: rgba(0, 212, 255, 0.08);
  border: 1px solid rgba(0, 212, 255, 0.2);
  border-radius: 8px;
  font-size: 14px;
  color: var(--primary);
}

/* Download Page */
.download-hero { padding: 100px 0 60px; text-align: center; }

.download-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  margin: 48px 0;
}

.download-card {
  background: var(--bg-card);
  border: 1px solid rgba(0, 212, 255, 0.1);
  border-radius: 16px;
  padding: 32px 24px;
  text-align: center;
  transition: border-color 0.3s, transform 0.3s;
}

.download-card:hover {
  border-color: rgba(0, 212, 255, 0.3);
  transform: translateY(-4px);
}

.download-card img { width: 48px; height: 48px; margin: 0 auto 16px; object-fit: contain; }
.download-card h3 { font-size: 18px; margin-bottom: 8px; }
.download-card p { color: var(--text-muted); font-size: 13px; margin-bottom: 20px; }

.download-card .btn-download { width: 100%; padding: 12px 24px; font-size: 15px; }

/* Steps */
.steps-list { counter-reset: step; max-width: 700px; margin: 0 auto; }

.step-item {
  display: flex;
  gap: 20px;
  margin-bottom: 32px;
  align-items: flex-start;
}

.step-item::before {
  counter-increment: step;
  content: counter(step);
  flex-shrink: 0;
  width: 40px; height: 40px;
  background: var(--gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 16px;
}

.step-item h3 { font-size: 16px; margin-bottom: 4px; }
.step-item p { color: var(--text-muted); font-size: 14px; }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }

.faq-item {
  border-bottom: 1px solid rgba(255,255,255,0.06);
  padding: 20px 0;
}

.faq-item h3 { font-size: 16px; margin-bottom: 8px; color: var(--text); }
.faq-item p { color: var(--text-muted); font-size: 14px; line-height: 1.7; }

/* SEO Content Block */
.seo-content {
  max-width: 900px;
  margin: 0 auto;
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.8;
}

.seo-content h2 { color: var(--text); font-size: 20px; margin: 32px 0 12px; }
.seo-content h3 { color: var(--text); font-size: 16px; margin: 24px 0 8px; }
.seo-content p { margin-bottom: 12px; }
.seo-content ul { padding-left: 20px; margin-bottom: 12px; }
.seo-content li { margin-bottom: 6px; }

/* Footer */
.site-footer {
  background: #060a10;
  border-top: 1px solid rgba(0, 212, 255, 0.08);
  padding: 48px 0 24px;
  margin-top: 40px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 32px;
  margin-bottom: 32px;
}

.footer-col h4 { font-size: 14px; color: var(--primary); margin-bottom: 12px; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 8px; }
.footer-col a { color: var(--text-muted); font-size: 13px; }

.footer-bottom {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.05);
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.8;
}

.breadcrumb {
  padding: 80px 0 0;
  font-size: 13px;
  color: var(--text-muted);
}

.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--primary); }

/* Mobile Nav Toggle */
.menu-toggle { display: none; background: none; border: none; color: var(--text); font-size: 24px; cursor: pointer; }

@media (max-width: 768px) {
  .menu-toggle { display: block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 64px; left: 0; right: 0;
    background: rgba(10, 14, 23, 0.98);
    flex-direction: column;
    padding: 20px;
    gap: 16px;
    border-bottom: 1px solid rgba(0, 212, 255, 0.1);
  }
  .nav-links.open { display: flex; }
  .header-cta { display: none; }
  .hero { padding: 100px 0 60px; }
  .section { padding: 60px 0; }
}