* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", Arial, sans-serif;
  color: #eaf4ff;
  background:
    radial-gradient(circle at 20% 20%, rgba(79, 209, 255, 0.18), transparent 28%),
    radial-gradient(circle at 80% 10%, rgba(24, 140, 255, 0.16), transparent 30%),
    linear-gradient(135deg, #050b14 0%, #07111f 45%, #0b1f35 100%);
  line-height: 1.8;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px 8%;
  background: rgba(7, 17, 31, 0.92);
  border-bottom: 1px solid rgba(80, 180, 255, 0.2);
}

header h1 {
  margin: 0;
  font-size: 24px;
  color: #ffffff;
}

nav a {
  color: #cfe9ff;
  text-decoration: none;
  margin-left: 28px;
  font-size: 15px;
}

nav a.active {
  color: #4fd1ff;
  font-weight: 600;
  border-bottom: 2px solid #4fd1ff;
  padding-bottom: 6px;
}

main {
  padding: 60px 8%;
}

section {
  max-width: 1100px;
  margin: 0 auto 70px;
}

h2 {
  font-size: 36px;
  line-height: 1.3;
  color: #ffffff;
  margin-bottom: 20px;
}

h3 {
  color: #4fd1ff;
  margin-top: 28px;
}

p {
  color: #b9d3e8;
  font-size: 17px;
}

ul {
  padding-left: 20px;
}

li {
  margin-bottom: 12px;
  color: #b9d3e8;
}

a {
  color: #4fd1ff;
}

footer {
  padding: 30px 8%;
  border-top: 1px solid rgba(80, 180, 255, 0.2);
  background: #050b14;
}

footer p {
  margin: 6px 0;
  font-size: 14px;
}

main section:first-child {
  position: relative;
  padding: 100px 0;
  overflow: hidden;
}

main section:first-child h2 {
  font-size: 48px;
  background: linear-gradient(90deg, #ffffff, #4fd1ff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

main section:first-child a {
  display: inline-block;
  margin-right: 16px;
  margin-top: 18px;
  padding: 10px 22px;
  border-radius: 999px;
  background: linear-gradient(90deg, #188cff, #4fd1ff);
  color: #ffffff;
  text-decoration: none;
}

main section:first-child a:last-child {
  background: transparent;
  border: 1px solid #4fd1ff;
  color: #4fd1ff;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.card {
  padding: 26px;
  border-radius: 18px;
  background: rgba(14, 33, 58, 0.85);
  border: 1px solid rgba(79, 209, 255, 0.18);
  box-shadow: 0 18px 45px rgba(0, 0, 0, 0.22);
}

.card h3 {
  margin-top: 0;
  font-size: 22px;
}

.card p {
  font-size: 15px;
}

@media (max-width: 768px) {
  header {
    display: block;
  }

  nav {
    margin-top: 16px;
  }

  nav a {
    display: inline-block;
    margin-left: 0;
    margin-right: 16px;
    margin-bottom: 8px;
  }

  main {
    padding: 36px 6%;
  }

  h2 {
    font-size: 30px;
  }

  main section:first-child h2 {
    font-size: 38px;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }
}

main section:first-child::before {
  content: "";
  position: absolute;
  right: 4%;
  top: 20%;
  width: 260px;
  height: 260px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(79, 209, 255, 0.26), transparent 65%);
  filter: blur(8px);
  z-index: -1;
}

main section:first-child::after {
  content: "";
  position: absolute;
  right: 8%;
  top: 26%;
  width: 180px;
  height: 180px;
  border: 1px solid rgba(79, 209, 255, 0.28);
  border-radius: 50%;
  box-shadow:
    0 0 40px rgba(79, 209, 255, 0.22),
    inset 0 0 35px rgba(79, 209, 255, 0.12);
  z-index: -1;
}