/* ===== Tencent Yuanbao — TDesign Blue Theme ===== */
:root {
  --brand: #0052D9;
  --brand-hover: #003CAB;
  --brand-light: #366EF4;
  --brand-gradient: linear-gradient(135deg, #0052D9 0%, #366EF4 100%);
  --brand-bg: #F2F3FF;
  --accent-green: #2CCA78;
  --warm-bg: #FFF1E9;
  --bg: #F5F7FA;
  --surface: #FFFFFF;
  --text-1: rgba(0,0,0,0.90);
  --text-2: rgba(0,0,0,0.60);
  --text-3: rgba(0,0,0,0.40);
  --border: #E7E7E7;
  --border-light: #F0F0F0;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
  --shadow: 0 4px 16px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
  --radius: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --font: "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-number: "TCloudNumber", "PingFang SC", sans-serif;
  --max-width: 1200px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--font); background: var(--bg);
  color: var(--text-1); line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
.wrap { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

/* ===== NAVBAR — TDesign Style ===== */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,0.88);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-light);
}
.navbar .wrap {
  display: flex; align-items: center; justify-content: space-between;
  height: 56px;
}
.nav-logo {
  display: flex; align-items: center; gap: 8px;
  text-decoration: none; font-weight: 600; font-size: 18px; color: var(--text-1);
}
.nav-logo-icon {
  width: 32px; height: 32px;
  background: var(--brand-gradient);
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 700; font-size: 16px;
}
.nav-links { display: flex; gap: 4px; align-items: center; }
.nav-link {
  padding: 6px 16px; border-radius: 6px;
  font-size: 14px; color: var(--text-2); text-decoration: none;
  font-weight: 500; transition: all 0.2s;
}
.nav-link:hover { color: var(--brand); background: var(--brand-bg); }
.nav-link.active { color: var(--brand); background: var(--brand-bg); font-weight: 600; }
.nav-dl-btn {
  margin-left: 12px; padding: 8px 20px;
  background: var(--brand); color: #fff;
  border-radius: 6px; font-size: 14px; font-weight: 600;
  text-decoration: none; transition: all 0.2s;
}
.nav-dl-btn:hover { background: var(--brand-hover); box-shadow: var(--shadow-sm); }

/* ===== HERO ===== */
.hero {
  padding: 80px 0 60px; text-align: center;
}
.hero-img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto 32px;
  border-radius: var(--radius-xl);
}
.hero-greeting {
  display: inline-flex; align-items: center; gap: 6px;
  background: var(--warm-bg);
  padding: 8px 20px; border-radius: 20px;
  font-size: 14px; color: #E37318; font-weight: 500;
  margin-bottom: 24px;
}
.hero h1 {
  font-size: 48px; font-weight: 700; letter-spacing: -0.5px;
  margin-bottom: 12px; line-height: 1.2;
}
.hero h1 .gradient-text {
  background: var(--brand-gradient);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-desc {
  font-size: 18px; color: var(--text-2); max-width: 600px;
  margin: 0 auto 40px; line-height: 1.6;
}

/* Platform cards */
.platform-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px; max-width: 800px; margin: 0 auto 48px;
}
.platform-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 28px 24px;
  text-decoration: none; color: var(--text-1);
  transition: all 0.3s; display: flex; flex-direction: column; gap: 12px;
}
.platform-card:hover {
  border-color: var(--brand); box-shadow: var(--shadow);
  transform: translateY(-2px);
}
.platform-card-header {
  display: flex; align-items: center; gap: 12px;
}
.platform-icon {
  width: 48px; height: 48px; border-radius: 12px;
  background: var(--brand-bg);
  display: flex; align-items: center; justify-content: center;
  font-size: 24px;
}
.platform-card h3 {
  font-size: 18px; font-weight: 600;
}
.platform-card p {
  font-size: 13px; color: var(--text-2);
}
.platform-meta {
  display: flex; gap: 12px; font-size: 12px; color: var(--text-3);
}
.platform-card .dl-link {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 8px 20px; background: var(--brand);
  color: #fff; border-radius: 6px; font-size: 14px;
  font-weight: 600; text-decoration: none; margin-top: auto;
  transition: background 0.2s;
}
.platform-card .dl-link:hover { background: var(--brand-hover); }

/* ===== FEATURES ===== */
.section { padding: 80px 0; }
.section-heading {
  text-align: center; font-size: 36px; font-weight: 700;
  margin-bottom: 12px; letter-spacing: -0.5px;
}
.section-sub {
  text-align: center; color: var(--text-2); font-size: 16px;
  margin-bottom: 48px;
}

.features-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}
.feature-card {
  background: var(--surface); border: 1px solid var(--border-light);
  border-radius: var(--radius-lg); padding: 28px 24px;
  transition: all 0.3s;
}
.feature-card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.feature-icon {
  width: 44px; height: 44px; border-radius: 10px;
  background: var(--brand-bg);
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; margin-bottom: 16px;
}
.feature-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: var(--text-2); line-height: 1.6; }

/* ===== DOWNLOAD SECTION ===== */
.dl-section { background: var(--surface); padding: 80px 0; }
.dl-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}
.dl-card {
  background: var(--bg); border: 2px solid transparent;
  border-radius: var(--radius-xl); padding: 36px 32px;
  text-align: center; transition: all 0.3s;
}
.dl-card:hover { border-color: var(--brand); box-shadow: var(--shadow-lg); }
.dl-card.recommended { border-color: var(--brand); position: relative; }
.dl-card .badge {
  position: absolute; top: -12px; left: 50%; transform: translateX(-50%);
  background: var(--brand); color: #fff; padding: 4px 16px;
  border-radius: 20px; font-size: 12px; font-weight: 600;
}
.dl-card-icon { font-size: 40px; margin-bottom: 16px; }
.dl-card h3 { font-size: 22px; font-weight: 700; margin-bottom: 4px; }
.dl-card .ver { font-size: 13px; color: var(--text-2); margin-bottom: 16px; }
.dl-card .dl-btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 12px 36px; background: var(--brand);
  color: #fff; border-radius: 8px; font-size: 16px;
  font-weight: 600; text-decoration: none;
  transition: all 0.2s;
}
.dl-card .dl-btn:hover { background: var(--brand-hover); transform: scale(1.03); }
.dl-card .dl-btn.outline {
  background: transparent; color: var(--brand);
  border: 2px solid var(--brand);
}
.dl-card .dl-btn.outline:hover { background: var(--brand-bg); }
.dl-card .dl-info {
  margin-top: 12px; font-size: 12px; color: var(--text-3);
}

/* ===== FAQ ===== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--surface); border: 1px solid var(--border-light);
  border-radius: var(--radius); margin-bottom: 8px; overflow: hidden;
}
.faq-q {
  padding: 16px 20px; font-size: 16px; font-weight: 500;
  cursor: pointer; display: flex; justify-content: space-between;
  align-items: center; user-select: none; color: var(--text-1);
  transition: color 0.2s;
}
.faq-q:hover { color: var(--brand); }
.faq-q::after { content: '+'; font-size: 20px; color: var(--text-3); transition: transform 0.3s; }
.faq-item.open .faq-q::after { content: '−'; transform: rotate(90deg); }
.faq-a { padding: 0 20px 16px; font-size: 14px; color: var(--text-2); line-height: 1.7; display: none; }
.faq-item.open .faq-a { display: block; }

/* ===== CTA ===== */
.cta-section {
  text-align: center; padding: 80px 0;
  background: var(--brand-gradient); color: #fff;
}
.cta-section h2 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.cta-section p { font-size: 16px; opacity: 0.85; margin-bottom: 36px; }
.cta-section .dl-btn-white {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 14px 40px; background: #fff; color: var(--brand);
  border-radius: 8px; font-size: 16px; font-weight: 700;
  text-decoration: none; transition: all 0.2s;
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}
.cta-section .dl-btn-white:hover { transform: scale(1.03); box-shadow: 0 6px 24px rgba(0,0,0,0.2); }

/* ===== FOOTER ===== */
.footer { background: #1A1C20; color: #8E8E93; padding: 56px 0 28px; }
.footer a { color: #8E8E93; text-decoration: none; font-size: 14px; transition: color 0.2s; }
.footer a:hover { color: #fff; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 48px; margin-bottom: 36px; }
.footer-brand h4 { color: #fff; font-size: 16px; margin-bottom: 10px; }
.footer-brand p { font-size: 13px; line-height: 1.7; }
.footer-col h4 { color: #fff; font-size: 13px; font-weight: 600; margin-bottom: 14px; text-transform: uppercase; letter-spacing: 0.05em; }
.footer-col a { display: block; margin-bottom: 10px; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.08); padding-top: 20px; display: flex; justify-content: space-between; font-size: 12px; flex-wrap: wrap; gap: 12px; }
.footer-disclaimer { margin-top: 12px; font-size: 11px; color: #666; }

@media (max-width: 768px) {
  .hero h1 { font-size: 32px; }
  .section-heading { font-size: 28px; }
  .platform-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr; }
  .dl-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .nav-links { display: none; }
}
@media (max-width: 480px) {
  .hero h1 { font-size: 26px; }
  .footer-grid { grid-template-columns: 1fr; }
}