* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --primary: #2f5de0;
  --primary-dark: #1e40af;
  --text: #1f2937;
  --muted: #6b7280;
}

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: #fff;
  line-height: 1.6;
}

/* ===== 顶部导航 ===== */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid #eef0f4;
}
.nav {
  max-width: 1120px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
}
.logo-mark {
  width: 28px; height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, #4a7dff, #2f5de0);
}
.nav-links { display: flex; gap: 28px; }
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 15px;
  transition: color .2s;
}
.nav-links a:hover { color: var(--primary); }

/* ===== 轮播横幅 ===== */
.carousel {
  position: relative;
  height: 460px;
  overflow: hidden;
}
.slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 1s ease-in-out;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: #fff;
  padding: 0 20px;
}
.slide.active { opacity: 1; }
.slide h2 {
  font-size: 40px;
  font-weight: 700;
  margin-bottom: 16px;
  animation: rise .9s ease both;
}
.slide p {
  font-size: 18px;
  opacity: .92;
  max-width: 560px;
  animation: rise 1.1s ease both;
}
.slide:nth-child(1) { background: linear-gradient(135deg, #4a7dff 0%, #2f5de0 100%); }
.slide:nth-child(2) { background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%); }
.slide:nth-child(3) { background: linear-gradient(135deg, #fc5c7d 0%, #6a82fb 100%); }

.dots {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 5;
}
.dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,.5);
  cursor: pointer;
  transition: background .3s, width .3s;
}
.dot.active { background: #fff; width: 26px; border-radius: 6px; }

@keyframes rise {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ===== 特性卡片 ===== */
.section {
  max-width: 1120px;
  margin: 0 auto;
  padding: 72px 24px;
}
.section-title {
  text-align: center;
  font-size: 30px;
  font-weight: 700;
  margin-bottom: 12px;
}
.section-sub {
  text-align: center;
  color: var(--muted);
  margin-bottom: 48px;
}
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}
.feature {
  background: #fff;
  border: 1px solid #eef0f4;
  border-radius: 16px;
  padding: 32px 28px;
  transition: transform .3s, box-shadow .3s;
  opacity: 0;
  transform: translateY(30px);
}
.feature.reveal {
  opacity: 1;
  transform: translateY(0);
}
.feature:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 40px rgba(47, 93, 224, 0.12);
}
.feature .icon {
  width: 56px; height: 56px;
  border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 26px;
  margin-bottom: 20px;
  background: #f0f5ff;
}
.feature h3 { font-size: 19px; margin-bottom: 10px; }
.feature p { color: var(--muted); font-size: 15px; }

/* ===== 底部 ===== */
footer {
  background: #0f172a;
  color: #94a3b8;
  padding: 40px 24px 28px;
  text-align: center;
}
.footer-inner { max-width: 1120px; margin: 0 auto; }
.footer-links { margin-bottom: 18px; }
.footer-links a {
  color: #cbd5e1;
  text-decoration: none;
  margin: 0 14px;
  font-size: 14px;
}
.footer-links a:hover { color: #fff; }
.beian {
  font-size: 13px;
  line-height: 2;
  border-top: 1px solid #1e293b;
  padding-top: 18px;
}
.beian a {
  color: #94a3b8;
  text-decoration: none;
}
.beian a:hover { color: #fff; text-decoration: underline; }

@media (max-width: 640px) {
  .nav-links { display: none; }
  .carousel { height: 360px; }
  .slide h2 { font-size: 28px; }
  .slide p { font-size: 15px; }
}