/* === 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, "PingFang SC", "Microsoft YaHei", "Inter", "SF Pro", "Roboto", sans-serif;
  color: #1E293B; background: #fff; line-height: 1.6; overflow-x: hidden;
}
a { text-decoration: none; color: inherit; transition: color .2s; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

/* === Utility === */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-alt { background: #F8FAFC; }
.text-center { text-align: center; }
.section-title { font-size: 36px; font-weight: 700; margin-bottom: 16px; color: #1E293B; }
.section-subtitle { font-size: 18px; color: #64748B; margin-bottom: 48px; max-width: 640px; margin-left: auto; margin-right: auto; }

/* === Buttons === */
.btn {
  display: inline-block; padding: 14px 32px; border-radius: 8px; font-size: 16px;
  font-weight: 600; text-align: center; cursor: pointer; transition: all .25s;
}
.btn-primary { background: #2563EB; color: #fff; }
.btn-primary:hover { background: #1d4ed8; transform: translateY(-1px); box-shadow: 0 4px 12px rgba(37,99,235,.35); }
.btn-outline { border: 2px solid #2563EB; color: #2563EB; background: transparent; }
.btn-outline:hover { background: #2563EB; color: #fff; }
.btn-white { background: #fff; color: #2563EB; }
.btn-white:hover { background: #f0f4ff; transform: translateY(-1px); }
.btn-sm { padding: 10px 24px; font-size: 14px; }
.btn-lg { padding: 18px 40px; font-size: 18px; }

/* === Header === */
.header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(255,255,255,.95); backdrop-filter: blur(10px);
  border-bottom: 1px solid #e2e8f0; height: 72px;
}
.header .container { display: flex; align-items: center; justify-content: space-between; height: 100%; }
.logo { font-size: 24px; font-weight: 800; color: #2563EB; letter-spacing: -0.5px; }
.logo span { color: #1E293B; }
.nav { display: flex; align-items: center; gap: 32px; }
.nav a { font-size: 15px; color: #475569; font-weight: 500; transition: color .2s; }
.nav a:hover { color: #2563EB; }
.nav-cta { margin-left: 8px; }
.menu-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; }
.menu-toggle span { width: 24px; height: 2px; background: #1E293B; border-radius: 2px; }

/* === Hero === */
.hero {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 50%, #bfdbfe 100%);
  padding-top: 72px; text-align: center; position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; top: -50%; right: -20%; width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(37,99,235,.08) 0%, transparent 70%);
  border-radius: 50%;
}
.hero-content { position: relative; z-index: 1; max-width: 800px; padding: 0 24px; }
.hero h1 { font-size: 52px; font-weight: 800; line-height: 1.2; margin-bottom: 20px; color: #0f172a; }
.hero h1 em { font-style: normal; color: #2563EB; }
.hero .subtitle { font-size: 20px; color: #475569; margin-bottom: 40px; line-height: 1.6; }
.hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 48px; }
.trust-badges { display: flex; gap: 32px; justify-content: center; flex-wrap: wrap; }
.trust-badge { display: flex; align-items: center; gap: 8px; color: #64748B; font-size: 14px; }
.trust-badge .badge-icon { width: 20px; height: 20px; background: #2563EB; border-radius: 50%; display: flex; align-items: center; justify-content: center; color: #fff; font-size: 12px; font-weight: 700; }

/* === Features Grid === */
.features-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px; }
.feature-card {
  background: #fff; border: 1px solid #e2e8f0; border-radius: 16px; padding: 40px;
  transition: all .3s;
}
.feature-card:hover { border-color: #93c5fd; box-shadow: 0 8px 24px rgba(37,99,235,.08); transform: translateY(-2px); }
.feature-icon {
  width: 56px; height: 56px; border-radius: 12px; display: flex; align-items: center;
  justify-content: center; font-size: 24px; margin-bottom: 20px;
}
.feature-icon.blue { background: #dbeafe; color: #2563EB; }
.feature-icon.green { background: #dcfce7; color: #16a34a; }
.feature-icon.purple { background: #ede9fe; color: #7c3aed; }
.feature-icon.orange { background: #ffedd5; color: #ea580c; }
.feature-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 12px; }
.feature-card p { color: #64748B; font-size: 15px; line-height: 1.7; }

/* === Advantages === */
.advantage-item { display: flex; align-items: center; gap: 64px; margin-bottom: 64px; }
.advantage-item:last-child { margin-bottom: 0; }
.advantage-item.reverse { flex-direction: row-reverse; }
.advantage-text { flex: 1; }
.advantage-text h3 { font-size: 28px; font-weight: 700; margin-bottom: 16px; }
.advantage-text p { color: #64748B; font-size: 16px; line-height: 1.8; margin-bottom: 16px; }
.advantage-visual {
  flex: 1; background: linear-gradient(135deg, #eff6ff, #dbeafe); border-radius: 20px;
  padding: 48px; display: flex; align-items: center; justify-content: center; min-height: 280px;
}
.advantage-visual .visual-icon { font-size: 80px; }

/* === Platform === */
.platform-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.platform-card {
  background: #fff; border: 1px solid #e2e8f0; border-radius: 16px; padding: 32px;
  text-align: center; transition: all .3s;
}
.platform-card:hover { border-color: #93c5fd; box-shadow: 0 8px 24px rgba(37,99,235,.08); transform: translateY(-2px); }
.platform-icon { font-size: 48px; margin-bottom: 16px; }
.platform-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.platform-card .version { color: #94a3b8; font-size: 13px; margin-bottom: 16px; }

/* === Testimonials === */
.testimonials-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-bottom: 48px; }
.testimonial-card {
  background: #fff; border: 1px solid #e2e8f0; border-radius: 16px; padding: 32px;
}
.testimonial-card .stars { color: #f59e0b; font-size: 18px; margin-bottom: 16px; }
.testimonial-card .quote { color: #475569; font-size: 15px; line-height: 1.7; margin-bottom: 20px; font-style: italic; }
.testimonial-card .author { font-weight: 600; font-size: 14px; }
.testimonial-card .role { color: #94a3b8; font-size: 13px; }
.stats-row { display: flex; justify-content: center; gap: 64px; flex-wrap: wrap; }
.stat-item { text-align: center; }
.stat-item .stat-number { font-size: 42px; font-weight: 800; color: #2563EB; }
.stat-item .stat-label { font-size: 14px; color: #64748B; margin-top: 4px; }

/* === Pricing === */
.pricing-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.pricing-card {
  background: #fff; border: 1px solid #e2e8f0; border-radius: 16px; padding: 32px;
  text-align: center; transition: all .3s; position: relative;
}
.pricing-card:hover { border-color: #93c5fd; box-shadow: 0 8px 24px rgba(37,99,235,.08); }
.pricing-card.popular { border-color: #2563EB; box-shadow: 0 8px 24px rgba(37,99,235,.12); }
.pricing-card.popular::before {
  content: 'HOT'; position: absolute; top: -12px; left: 50%; transform: translateX(-50%);
  background: #2563EB; color: #fff; font-size: 12px; font-weight: 700; padding: 4px 16px;
  border-radius: 20px;
}
.pricing-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.pricing-card .price { font-size: 36px; font-weight: 800; color: #2563EB; margin-bottom: 4px; }
.pricing-card .price-unit { font-size: 14px; color: #94a3b8; margin-bottom: 20px; }
.pricing-card .price-desc { color: #64748B; font-size: 14px; margin-bottom: 24px; line-height: 1.6; }

/* === FAQ === */
.faq-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.faq-card {
  background: #fff; border: 1px solid #e2e8f0; border-radius: 16px; padding: 32px;
}
.faq-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 16px; color: #2563EB; }
.faq-card .faq-q { font-weight: 600; margin-bottom: 12px; font-size: 15px; }
.faq-card .faq-a { color: #64748B; font-size: 14px; line-height: 1.8; }
.faq-card .faq-a ol { padding-left: 20px; list-style: decimal; }
.faq-card .faq-a ol li { margin-bottom: 6px; }

/* === CTA Banner === */
.cta-banner {
  background: linear-gradient(135deg, #2563EB, #1d4ed8);
  padding: 80px 0; text-align: center; color: #fff;
}
.cta-banner h2 { font-size: 36px; font-weight: 700; margin-bottom: 16px; }
.cta-banner p { font-size: 18px; opacity: .9; margin-bottom: 32px; }

/* === Footer === */
.footer { background: #0f172a; color: #94a3b8; padding: 64px 0 32px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 48px; margin-bottom: 48px; }
.footer-brand .logo { color: #fff; font-size: 22px; margin-bottom: 16px; display: inline-block; }
.footer-brand .logo span { color: #93c5fd; }
.footer-brand p { font-size: 14px; line-height: 1.7; }
.footer h4 { color: #e2e8f0; font-size: 15px; font-weight: 600; margin-bottom: 20px; }
.footer ul li { margin-bottom: 12px; }
.footer ul li a { font-size: 14px; color: #94a3b8; transition: color .2s; }
.footer ul li a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid #1e293b; padding-top: 24px; text-align: center; font-size: 13px; }

/* === Floating CTA === */
.floating-cta {
  position: fixed; bottom: 24px; right: 24px; z-index: 999;
}
.floating-cta .btn { box-shadow: 0 4px 16px rgba(37,99,235,.4); border-radius: 50px; padding: 16px 28px; }

/* === Page Header (inner pages) === */
.page-header {
  padding: 140px 0 60px; text-align: center;
  background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 100%);
}
.page-header h1 { font-size: 42px; font-weight: 800; margin-bottom: 16px; }
.page-header p { font-size: 18px; color: #64748B; max-width: 600px; margin: 0 auto; }

/* === Download Page === */
.download-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px; max-width: 800px; margin: 0 auto; }
.download-card {
  background: #fff; border: 1px solid #e2e8f0; border-radius: 16px; padding: 40px;
  text-align: center; transition: all .3s;
}
.download-card:hover { border-color: #93c5fd; box-shadow: 0 8px 24px rgba(37,99,235,.08); transform: translateY(-2px); }
.download-card .platform-icon { font-size: 56px; margin-bottom: 16px; }
.download-card h3 { font-size: 22px; font-weight: 700; margin-bottom: 8px; }
.download-card .version { color: #94a3b8; font-size: 13px; margin-bottom: 20px; }

/* === Help Page === */
.help-categories { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-bottom: 64px; }
.help-cat-card {
  background: #fff; border: 1px solid #e2e8f0; border-radius: 16px; padding: 32px;
  text-align: center; transition: all .3s;
}
.help-cat-card:hover { border-color: #93c5fd; transform: translateY(-2px); }
.help-cat-card .cat-icon { font-size: 40px; margin-bottom: 16px; }
.help-cat-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.help-cat-card p { color: #64748B; font-size: 14px; }

/* === Privacy / Terms === */
.legal-content { max-width: 800px; margin: 0 auto; }
.legal-content h2 { font-size: 24px; font-weight: 700; margin: 32px 0 16px; }
.legal-content p { color: #475569; font-size: 15px; line-height: 1.8; margin-bottom: 16px; }
.legal-content ul { padding-left: 24px; list-style: disc; margin-bottom: 16px; }
.legal-content ul li { color: #475569; font-size: 15px; line-height: 1.8; margin-bottom: 8px; }

/* === Certifications === */
.cert-row { display: flex; justify-content: center; gap: 48px; flex-wrap: wrap; margin-bottom: 48px; }
.cert-item { text-align: center; }
.cert-item .cert-badge {
  width: 80px; height: 80px; background: #f0f4ff; border: 2px solid #bfdbfe;
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  font-size: 32px; margin: 0 auto 12px;
}
.cert-item .cert-name { font-size: 13px; color: #64748B; font-weight: 500; }

/* === Responsive === */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .platform-grid { grid-template-columns: repeat(2, 1fr); }
  .pricing-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .advantage-item { gap: 40px; }
}
@media (max-width: 768px) {
  .section { padding: 56px 0; }
  .section-title { font-size: 28px; }
  .hero h1 { font-size: 32px; }
  .hero .subtitle { font-size: 16px; }
  .nav { display: none; }
  .menu-toggle { display: flex; }
  .features-grid { grid-template-columns: 1fr; }
  .platform-grid { grid-template-columns: repeat(2, 1fr); }
  .pricing-grid { grid-template-columns: 1fr; }
  .testimonials-grid { grid-template-columns: 1fr; }
  .faq-grid { grid-template-columns: 1fr; }
  .download-grid { grid-template-columns: 1fr; }
  .help-categories { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .advantage-item, .advantage-item.reverse { flex-direction: column; gap: 32px; }
  .stats-row { gap: 32px; }
  .trust-badges { gap: 16px; }
  .page-header h1 { font-size: 30px; }
  .cta-banner h2 { font-size: 26px; }
  .hero-btns { flex-direction: column; align-items: center; }
  .cert-row { gap: 24px; }
}