/* Bitibrowser static site shared styles */
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  color: #1a1a2e;
  background: #ffffff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

:root {
  --primary: #2f6bff;
  --primary-dark: #1e50d9;
  --purple: #6c5ce7;
  --bg-soft: #f5f7ff;
  --text-dim: #5b6479;
  --border: #e6e9f2;
  --radius: 10px;
}

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

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.site-header .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.logo { display:flex; align-items:center; gap:8px; font-weight:700; font-size:20px; color:var(--primary); }
.logo-mark {
  width:32px; height:32px; border-radius:8px;
  background: linear-gradient(135deg, var(--primary), var(--purple));
  color:#fff; display:flex; align-items:center; justify-content:center;
  font-weight:800; font-size:16px;
}
.nav { display:flex; align-items:center; gap:28px; }
.nav a { font-size:15px; color:#1a1a2e; font-weight:500; transition:color .2s; }
.nav a:hover { color:var(--primary); }
.nav-actions { display:flex; align-items:center; gap:12px; }
.lang-switch { font-size:14px; color:var(--text-dim); }
.btn {
  display:inline-block; padding:10px 22px; border-radius:999px;
  font-weight:600; font-size:14px; transition: all .2s; cursor:pointer;
  border:1px solid transparent;
}
.btn-primary { background: var(--primary); color:#fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline { border-color: var(--primary); color: var(--primary); background:#fff; }
.btn-outline:hover { background: var(--primary); color:#fff; }
.btn-lg { padding:14px 32px; font-size:16px; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(180deg, #eef2ff 0%, #ffffff 100%);
  padding: 80px 0 60px;
}
.hero-grid {
  display:grid; grid-template-columns: 1fr 1fr; gap:40px; align-items:center;
}
.hero h1 {
  font-size: 52px; line-height:1.15; font-weight:800;
  background: linear-gradient(90deg, var(--primary), var(--purple));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  margin-bottom: 16px;
}
.hero .subtitle { font-size:32px; font-weight:700; color:#1a1a2e; margin-bottom:20px; }
.hero .lead { font-size:16px; color:var(--text-dim); margin-bottom:32px; max-width:520px; }
.hero-ctas { display:flex; gap:14px; flex-wrap:wrap; }
.hero-image img { width:100%; border-radius: var(--radius); }

/* ---------- Sections ---------- */
section { padding: 72px 0; }
.section-title {
  text-align:center; font-size:36px; font-weight:800; margin-bottom:14px;
}
.section-sub { text-align:center; color:var(--text-dim); margin-bottom:48px; font-size:16px; }

.feature-grid {
  display:grid; grid-template-columns: repeat(3, 1fr); gap:24px;
}
.feature-card {
  padding:32px 24px; border:1px solid var(--border); border-radius:16px;
  background:#fff; transition: transform .2s, box-shadow .2s;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(47,107,255,.10); }
.feature-card h3 { font-size:18px; margin-bottom:10px; }
.feature-card p { color:var(--text-dim); font-size:14px; }
.feature-icon {
  width:48px; height:48px; border-radius:12px;
  background: linear-gradient(135deg, var(--primary), var(--purple));
  display:flex; align-items:center; justify-content:center;
  color:#fff; font-size:22px; font-weight:700; margin-bottom:16px;
}

.bg-soft { background: var(--bg-soft); }

.split { display:grid; grid-template-columns: 1fr 1fr; gap:48px; align-items:center; }
.split.reverse .split-text { order:2; }
.split h2 { font-size:32px; font-weight:800; margin-bottom:16px; }
.split p { color:var(--text-dim); margin-bottom:24px; }

.ecosystem-grid {
  display:grid; grid-template-columns: repeat(3,1fr); gap:24px;
}
.eco-card {
  padding:24px; border-radius:16px; background:#fff; border:1px solid var(--border);
}
.eco-card img { border-radius:8px; margin-top:12px; }

/* Testimonials */
.testimonials { display:grid; grid-template-columns: repeat(3,1fr); gap:24px; }
.testimonial {
  padding:28px; background:#fff; border-radius:16px; border:1px solid var(--border);
}
.t-user { display:flex; align-items:center; gap:12px; margin-bottom:16px; }
.avatar { width:48px; height:48px; border-radius:50%; background:linear-gradient(135deg,var(--primary),var(--purple)); color:#fff; display:flex; align-items:center; justify-content:center; font-weight:700; }
.testimonial p { color:var(--text-dim); font-size:14px; }

/* FAQ */
.faq-list { max-width:820px; margin:0 auto; }
.faq-item { border-bottom:1px solid var(--border); padding:22px 0; }
.faq-item summary {
  font-weight:600; font-size:17px; cursor:pointer; list-style:none;
  display:flex; justify-content:space-between; align-items:center;
}
.faq-item summary::-webkit-details-marker { display:none; }
.faq-item summary::after { content:"+"; font-size:22px; color:var(--primary); font-weight:400; }
.faq-item[open] summary::after { content:"−"; }
.faq-item p { margin-top:12px; color:var(--text-dim); }

/* CTA banner */
.cta-banner {
  background: linear-gradient(120deg, var(--primary), var(--purple));
  color:#fff; padding: 64px 0; text-align:center; border-radius:24px; margin:0 20px;
}
.cta-banner h2 { font-size:32px; margin-bottom:16px; color:#fff; }
.cta-banner .btn-primary { background:#fff; color:var(--primary); }
.cta-banner .btn-primary:hover { background:#f0f4ff; }

/* Footer */
.site-footer {
  background:#0f1226; color:#c0c6d9; padding:56px 0 24px; margin-top:72px;
}
.footer-grid { display:grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap:40px; }
.footer-grid h4 { color:#fff; font-size:16px; margin-bottom:16px; }
.footer-grid a { display:block; padding:6px 0; color:#c0c6d9; font-size:14px; }
.footer-grid a:hover { color:#fff; }
.footer-bottom {
  border-top:1px solid #22263e; margin-top:40px; padding-top:20px;
  text-align:center; font-size:13px; color:#8189a5;
}

/* Download page */
.download-grid { display:grid; grid-template-columns: repeat(3,1fr); gap:24px; }
.dl-card { padding:32px; border:1px solid var(--border); border-radius:16px; text-align:center; background:#fff; }
.dl-card img { width:64px; height:64px; margin:0 auto 16px; }
.dl-card h3 { margin-bottom:8px; }
.dl-card p { color:var(--text-dim); font-size:14px; margin-bottom:20px; }

/* Pricing */
.pricing-grid { display:grid; grid-template-columns: repeat(4,1fr); gap:20px; }
.price-card {
  padding:32px 24px; border:1px solid var(--border); border-radius:16px; background:#fff;
  position:relative; transition: transform .2s;
}
.price-card.featured { border-color: var(--primary); box-shadow: 0 16px 40px rgba(47,107,255,.15); transform: translateY(-8px); }
.price-card h3 { font-size:20px; margin-bottom:8px; }
.price-card .price { font-size:36px; font-weight:800; color:var(--primary); margin: 16px 0; }
.price-card .price small { font-size:14px; color:var(--text-dim); font-weight:400; }
.price-card ul { margin: 20px 0; }
.price-card li { padding:8px 0; color:var(--text-dim); font-size:14px; border-bottom:1px dashed var(--border); }
.badge {
  position:absolute; top:-10px; right:20px; background:var(--primary); color:#fff;
  padding:4px 12px; border-radius:999px; font-size:12px; font-weight:600;
}

/* Contact */
.contact-grid { display:grid; grid-template-columns: 1fr 1fr; gap:48px; }
.contact-card {
  padding:32px; background:#fff; border:1px solid var(--border); border-radius:16px;
  margin-bottom:20px;
}
.contact-card h3 { margin-bottom:12px; }
.contact-card p { color:var(--text-dim); }
.contact-form input, .contact-form textarea {
  width:100%; padding:14px; border:1px solid var(--border); border-radius:10px;
  font-family:inherit; font-size:14px; margin-bottom:14px;
}
.contact-form textarea { min-height:140px; resize:vertical; }

/* Page banner */
.page-banner {
  background: linear-gradient(180deg, #eef2ff 0%, #ffffff 100%);
  padding: 80px 0 48px; text-align:center;
}
.page-banner h1 {
  font-size:44px; font-weight:800; margin-bottom:14px;
  background: linear-gradient(90deg, var(--primary), var(--purple));
  -webkit-background-clip:text; background-clip:text; color:transparent;
}
.page-banner p { color:var(--text-dim); font-size:17px; max-width:640px; margin:0 auto; }

/* Responsive */
@media (max-width: 900px) {
  .hero-grid, .split, .contact-grid { grid-template-columns: 1fr; }
  .feature-grid, .ecosystem-grid, .testimonials, .download-grid { grid-template-columns: 1fr; }
  .pricing-grid { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .nav { display:none; }
  .hero h1 { font-size:36px; }
  .hero .subtitle { font-size:22px; }
  .section-title, .page-banner h1 { font-size:28px; }
}