:root {
  color-scheme: light;
  font-family: Poppins, "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  color: #161c2d;
  background: #fff;
}

* { box-sizing: border-box; }
body { margin: 0; background: #fff; color: #161c2d; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  display: flex;
  min-height: 76px;
  align-items: center;
  gap: 30px;
  padding: 12px max(24px, calc((100vw - 1200px) / 2));
  border-bottom: 1px solid rgba(22, 28, 45, .08);
  background: rgba(255, 255, 255, .96);
  backdrop-filter: blur(16px);
}

.brand { flex: 0 0 auto; }
.brand img { width: 190px; height: auto; }
.site-nav { display: flex; flex: 1; align-items: center; justify-content: center; gap: 28px; }
.site-nav a { padding: 10px 0; color: #4d5567; font-size: 14px; font-weight: 500; }
.site-nav a:hover, .site-nav a.active { color: #5a69e0; }
.header-actions { display: flex; align-items: center; gap: 10px; }

.button {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  transition: transform .18s ease, background .18s ease;
}
.button:hover { transform: translateY(-1px); }
.button-primary { background: #5a69e0; color: #fff; }
.button-primary:hover { background: #444cd3; }
.button-secondary { border-color: #dfe3ec; background: #fff; color: #161c2d; }
.button-light { background: #fff; color: #5a69e0; }

.lang-box { position: relative; }
.lang { display: flex; min-height: 42px; align-items: center; gap: 7px; padding: 8px 10px; border-radius: 9px; color: #3c4558; font-size: 13px; }
.lang:hover { background: #f2f4fa; }
.lang-icon { display: inline-flex; width: 24px; height: 24px; align-items: center; justify-content: center; border-radius: 50%; background: #eef0ff; color: #5a69e0; font-size: 12px; }
.lang-box .nav-wrapper {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  display: none;
  width: 176px;
  padding: 8px;
  border: 1px solid #e5e8ef;
  border-radius: 12px;
  background: #fff;
  box-shadow: 0 16px 40px rgba(22, 28, 45, .14);
}
.lang-box .nav-jump { display: block; padding: 9px 12px; border-radius: 8px; color: #3f4759; font-size: 13px; }
.lang-box .nav-jump:hover { background: #f1f3ff; color: #4b58c9; }

.hero {
  display: grid;
  min-height: 570px;
  align-items: center;
  grid-template-columns: minmax(0, 1.05fr) minmax(360px, .95fr);
  gap: 60px;
  max-width: 1280px;
  margin: 0 auto;
  padding: 80px 40px;
  background: radial-gradient(circle at 80% 20%, #e6e9ff 0, transparent 32%), linear-gradient(135deg, #f8f9ff, #fff 56%);
}
.hero-content { max-width: 650px; }
.eyebrow { display: inline-block; margin-bottom: 14px; color: #5a69e0; font-size: 13px; font-weight: 700; letter-spacing: .12em; }
h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 24px; font-size: clamp(42px, 5vw, 66px); line-height: 1.12; letter-spacing: -.035em; }
.hero p { max-width: 590px; margin-bottom: 34px; color: #626b7f; font-size: 18px; line-height: 1.8; }
.hero-buttons, .cta-actions { display: flex; flex-wrap: wrap; gap: 12px; }
.hero-image { width: 100%; max-height: 430px; object-fit: contain; filter: drop-shadow(0 28px 36px rgba(63, 72, 156, .16)); }

.content-section { max-width: 1200px; margin: 0 auto; padding: 96px 24px; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 40px; margin-bottom: 42px; }
.section-heading h2, .cta-section h2 { margin-bottom: 0; font-size: clamp(32px, 4vw, 48px); line-height: 1.18; }
.section-heading > p { max-width: 480px; margin-bottom: 4px; color: #697287; line-height: 1.7; }
.card-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 22px; }
.topic-card { min-height: 360px; padding: 34px; border: 1px solid rgba(90, 105, 224, .1); border-radius: 24px; }
.topic-card-purple { background: linear-gradient(145deg, #f0efff, #fbfaff); }
.topic-card-blue { background: linear-gradient(145deg, #eaf5ff, #f8fcff); }
.topic-card-green { background: linear-gradient(145deg, #eafaf4, #f8fffc); }
.topic-card img { width: 44px; height: 44px; margin-bottom: 30px; object-fit: contain; }
.card-tag { display: block; margin-bottom: 12px; color: #5a69e0; font-size: 13px; font-weight: 700; }
.topic-card h3 { margin-bottom: 16px; font-size: 23px; line-height: 1.45; }
.topic-card p { min-height: 76px; margin-bottom: 26px; color: #687186; font-size: 14px; line-height: 1.8; }
.topic-card a { color: #4b58c9; font-size: 14px; font-weight: 700; }

.cta-section { display: flex; max-width: 1200px; align-items: center; justify-content: space-between; gap: 40px; margin: 0 auto 96px; padding: 52px 56px; border-radius: 28px; background: #161c2d; color: #fff; }
.cta-section p { margin: 14px 0 0; color: #c6cada; }
.cta-section .eyebrow { color: #9fa9ff; }

.site-footer { padding: 54px max(24px, calc((100vw - 1200px) / 2)); background: #101522; color: #c4c9d5; }
.site-footer > img { width: 190px; margin-bottom: 20px; }
.site-footer p { margin-bottom: 24px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 24px; margin-bottom: 32px; }
.site-footer a:hover { color: #fff; }
.site-footer small { color: #7f8798; }

@media (max-width: 980px) {
  .site-header { flex-wrap: wrap; gap: 12px; }
  .site-nav { order: 3; width: 100%; overflow-x: auto; justify-content: flex-start; }
  .header-actions { margin-left: auto; }
  .hero { grid-template-columns: 1fr; padding-top: 60px; text-align: center; }
  .hero-content, .hero p { margin-right: auto; margin-left: auto; }
  .hero-buttons { justify-content: center; }
  .hero-image { max-height: 330px; }
  .card-grid { grid-template-columns: 1fr; }
  .topic-card { min-height: 0; }
  .topic-card p { min-height: 0; }
}

@media (max-width: 680px) {
  .site-header { position: static; padding: 14px 18px; }
  .brand img { width: 155px; }
  .header-actions .button-secondary, .lang-text { display: none; }
  .site-nav { gap: 20px; }
  .hero { min-height: 0; gap: 36px; padding: 52px 22px; }
  h1 { font-size: 40px; }
  .hero p { font-size: 16px; }
  .content-section { padding: 72px 18px; }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 16px; }
  .topic-card { padding: 28px; }
  .cta-section { display: block; margin: 0 18px 72px; padding: 38px 28px; }
  .cta-actions { margin-top: 28px; }
}