/* === Reset & Base === */
*, *::before, *::after { 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", "Hiragino Sans GB", "Microsoft YaHei", sans-serif; color: #333; line-height: 1.6; background: #fff; }
a { text-decoration: none; color: inherit; transition: color .2s; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* === Color Variables === */
:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --primary-light: #e8f0fe;
  --accent: #00c853;
  --dark: #1a2332;
  --dark-light: #2d3748;
  --gray: #64748b;
  --gray-light: #f1f5f9;
  --white: #ffffff;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);
  --radius: 12px;
  --radius-sm: 8px;
}

/* === Header / Navigation === */
.header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(255,255,255,0.95); backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(0,0,0,0.06);
  height: 70px; display: flex; align-items: center;
}
.header .container { display: flex; align-items: center; justify-content: space-between; width: 100%; }
.logo { display: flex; align-items: center; gap: 10px; font-size: 1.5rem; font-weight: 700; color: var(--primary); }
.logo-icon { width: 36px; height: 36px; background: var(--primary); border-radius: 8px; display: flex; align-items: center; justify-content: center; color: #fff; font-weight: 900; font-size: 1.1rem; }
.nav { display: flex; align-items: center; gap: 32px; }
.nav a { font-size: .95rem; color: var(--dark-light); font-weight: 500; padding: 6px 0; position: relative; }
.nav a:hover, .nav a.active { color: var(--primary); }
.nav a.active::after { content: ''; position: absolute; bottom: -2px; left: 0; right: 0; height: 2px; background: var(--primary); border-radius: 1px; }
.nav-download { background: var(--primary); color: #fff !important; padding: 10px 24px !important; border-radius: 8px; font-weight: 600; }
.nav-download:hover { background: var(--primary-dark); }
.nav-download::after { display: none !important; }

/* Mobile menu toggle */
.menu-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; }
.menu-toggle span { width: 24px; height: 2px; background: var(--dark); border-radius: 2px; }

/* === Hero Section === */
.hero {
  padding: 140px 0 100px; background: linear-gradient(135deg, #0a1628 0%, #1a365d 50%, #1a73e8 100%);
  color: #fff; text-align: center; position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%;
  background: radial-gradient(circle at 30% 50%, rgba(26,115,232,0.15) 0%, transparent 50%),
              radial-gradient(circle at 70% 80%, rgba(0,200,83,0.1) 0%, transparent 40%);
}
.hero-content { position: relative; z-index: 1; }
.hero h1 { font-size: 3rem; font-weight: 800; margin-bottom: 16px; letter-spacing: -0.02em; }
.hero .subtitle { font-size: 1.25rem; opacity: .85; margin-bottom: 40px; max-width: 600px; margin-left: auto; margin-right: auto; }
.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: 10px; font-size: 1rem; font-weight: 600;
  transition: all .25s; cursor: pointer; border: none;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #00b248; transform: translateY(-2px); box-shadow: 0 6px 20px rgba(0,200,83,0.35); }
.btn-outline { background: transparent; color: #fff; border: 2px solid rgba(255,255,255,0.4); }
.btn-outline:hover { border-color: #fff; background: rgba(255,255,255,0.1); }
.btn-blue { background: var(--primary); color: #fff; }
.btn-blue:hover { background: var(--primary-dark); transform: translateY(-2px); }

/* === Trust Section === */
.trust { padding: 60px 0; background: var(--gray-light); }
.trust-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.trust-item {
  text-align: center; padding: 30px 20px; background: #fff;
  border-radius: var(--radius); box-shadow: var(--shadow);
}
.trust-icon { font-size: 2.5rem; margin-bottom: 12px; }
.trust-item h3 { font-size: 1.1rem; color: var(--dark); margin-bottom: 6px; }
.trust-item p { font-size: .9rem; color: var(--gray); }

/* === Section Common === */
.section { padding: 80px 0; }
.section-title { text-align: center; margin-bottom: 50px; }
.section-title h2 { font-size: 2.2rem; font-weight: 700; color: var(--dark); margin-bottom: 12px; }
.section-title p { font-size: 1.1rem; color: var(--gray); max-width: 600px; margin: 0 auto; }
.section-alt { background: var(--gray-light); }

/* === Features Grid === */
.features-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 30px; }
.feature-card {
  padding: 36px; background: #fff; border-radius: var(--radius);
  box-shadow: var(--shadow); transition: all .3s; border: 1px solid transparent;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--primary-light); }
.feature-icon {
  width: 56px; height: 56px; border-radius: 14px; display: flex;
  align-items: center; justify-content: center; font-size: 1.6rem;
  margin-bottom: 18px; background: var(--primary-light); color: var(--primary);
}
.feature-card h3 { font-size: 1.2rem; color: var(--dark); margin-bottom: 10px; }
.feature-card p { font-size: .95rem; color: var(--gray); line-height: 1.7; }

/* === Platform Section === */
.platforms { padding: 80px 0; text-align: center; }
.platform-grid { display: flex; justify-content: center; gap: 40px; flex-wrap: wrap; margin-top: 40px; }
.platform-item {
  width: 140px; padding: 30px 20px; background: #fff; border-radius: var(--radius);
  box-shadow: var(--shadow); text-align: center; transition: all .3s;
}
.platform-item:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.platform-icon { font-size: 2.8rem; margin-bottom: 12px; color: var(--dark); }
.platform-item p { font-size: .9rem; color: var(--gray); font-weight: 500; }

/* === Pricing Section === */
.pricing-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.pricing-card {
  padding: 36px 24px; background: #fff; border-radius: var(--radius);
  box-shadow: var(--shadow); text-align: center; position: relative; border: 2px solid transparent;
  transition: all .3s;
}
.pricing-card:hover { border-color: var(--primary); transform: translateY(-4px); }
.pricing-card.featured { border-color: var(--primary); }
.pricing-badge {
  position: absolute; top: -12px; left: 50%; transform: translateX(-50%);
  background: var(--primary); color: #fff; padding: 4px 16px; border-radius: 20px;
  font-size: .8rem; font-weight: 600;
}
.pricing-card h3 { font-size: 1.2rem; color: var(--dark); margin-bottom: 8px; }
.pricing-price { font-size: 2rem; font-weight: 800; color: var(--primary); margin: 16px 0; }
.pricing-price span { font-size: .9rem; font-weight: 400; color: var(--gray); }
.pricing-features { margin: 20px 0; }
.pricing-features li { padding: 8px 0; font-size: .9rem; color: var(--gray); border-bottom: 1px solid var(--gray-light); }
.pricing-features li:last-child { border-bottom: none; }

/* === FAQ Section === */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: #fff; border-radius: var(--radius); margin-bottom: 16px;
  box-shadow: var(--shadow); overflow: hidden;
}
.faq-question {
  padding: 24px 30px; font-size: 1.05rem; font-weight: 600;
  color: var(--dark); cursor: pointer; display: flex; align-items: center; gap: 12px;
}
.faq-question::before {
  content: 'Q'; display: flex; align-items: center; justify-content: center;
  width: 32px; height: 32px; background: var(--primary); color: #fff;
  border-radius: 8px; font-size: .85rem; font-weight: 700; flex-shrink: 0;
}
.faq-answer { padding: 0 30px 24px 74px; color: var(--gray); line-height: 1.8; }
.faq-answer p { margin-bottom: 8px; }

/* === Page Header (for inner pages) === */
.page-header {
  padding: 120px 0 60px; background: linear-gradient(135deg, #0a1628 0%, #1a365d 100%);
  color: #fff; text-align: center;
}
.page-header h1 { font-size: 2.5rem; font-weight: 700; margin-bottom: 12px; }
.page-header p { font-size: 1.1rem; opacity: .8; max-width: 600px; margin: 0 auto; }

/* === Guide Steps === */
.guide-steps { max-width: 800px; margin: 0 auto; }
.guide-step {
  display: flex; gap: 24px; padding: 30px; background: #fff;
  border-radius: var(--radius); box-shadow: var(--shadow); margin-bottom: 20px;
}
.step-number {
  width: 48px; height: 48px; background: var(--primary); color: #fff;
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem; font-weight: 700; flex-shrink: 0;
}
.step-content h3 { font-size: 1.15rem; color: var(--dark); margin-bottom: 8px; }
.step-content p { font-size: .95rem; color: var(--gray); line-height: 1.7; }

/* === Download Cards === */
.download-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; max-width: 800px; margin: 0 auto; }
.download-card {
  display: flex; align-items: center; gap: 20px; padding: 30px;
  background: #fff; border-radius: var(--radius); box-shadow: var(--shadow);
  transition: all .3s;
}
.download-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.download-card-icon { font-size: 2.5rem; color: var(--primary); flex-shrink: 0; }
.download-card h3 { font-size: 1.1rem; color: var(--dark); margin-bottom: 6px; }
.download-card p { font-size: .85rem; color: var(--gray); margin-bottom: 12px; }
.download-card .btn { padding: 10px 24px; font-size: .9rem; }

/* === About Content === */
.about-content { max-width: 800px; margin: 0 auto; }
.about-block { margin-bottom: 40px; }
.about-block h3 { font-size: 1.3rem; color: var(--dark); margin-bottom: 12px; }
.about-block p { font-size: 1rem; color: var(--gray); line-height: 1.8; }
.cert-badges { display: flex; gap: 20px; flex-wrap: wrap; margin-top: 20px; }
.cert-badge {
  display: flex; align-items: center; gap: 10px; padding: 16px 24px;
  background: var(--primary-light); border-radius: var(--radius-sm); color: var(--primary);
  font-weight: 600; font-size: .95rem;
}

/* === Footer === */
.footer {
  background: var(--dark); color: rgba(255,255,255,0.7); padding: 60px 0 30px;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 40px; }
.footer-brand h3 { color: #fff; font-size: 1.3rem; margin-bottom: 12px; }
.footer-brand p { font-size: .9rem; line-height: 1.7; }
.footer-col h4 { color: #fff; font-size: 1rem; margin-bottom: 16px; }
.footer-col a { display: block; padding: 4px 0; font-size: .9rem; color: rgba(255,255,255,0.6); transition: color .2s; }
.footer-col a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.1); padding-top: 24px; text-align: center; font-size: .85rem; }

/* === Stats Section === */
.stats { padding: 60px 0; background: var(--primary); color: #fff; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; text-align: center; }
.stat-item h3 { font-size: 2.5rem; font-weight: 800; margin-bottom: 6px; }
.stat-item p { font-size: .95rem; opacity: .85; }

/* === CTA Section === */
.cta {
  padding: 80px 0; text-align: center;
  background: linear-gradient(135deg, #1a73e8 0%, #0a1628 100%); color: #fff;
}
.cta h2 { font-size: 2rem; font-weight: 700; margin-bottom: 16px; }
.cta p { font-size: 1.1rem; opacity: .85; margin-bottom: 30px; }

/* === Responsive === */
@media (max-width: 1024px) {
  .trust-grid { grid-template-columns: repeat(2, 1fr); }
  .pricing-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .hero .subtitle { font-size: 1rem; }
  .section-title h2 { font-size: 1.6rem; }
  .features-grid { grid-template-columns: 1fr; }
  .download-grid { grid-template-columns: 1fr; }
  .pricing-grid { grid-template-columns: 1fr; }
  .trust-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .nav { display: none; }
  .menu-toggle { display: flex; }
  .nav.open {
    display: flex; flex-direction: column; position: absolute;
    top: 70px; left: 0; right: 0; background: #fff;
    padding: 20px; box-shadow: var(--shadow-lg); gap: 16px;
  }
  .page-header h1 { font-size: 1.8rem; }
  .guide-step { flex-direction: column; gap: 12px; }
  .faq-answer { padding-left: 30px; }
}