body {
  margin: 0;
  font-family: 'Segoe UI', Arial, sans-serif;
  background: #f5f7fa;
  color: #222;
}

header {
  background: #fff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  position: sticky;
  top: 0;
  z-index: 100;
}
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}
.logo a {
  font-size: 2rem;
  font-weight: bold;
  color: #1a4e8a;
  text-decoration: none;
  letter-spacing: 1px;
  transition: color 0.2s;
}
.logo a:hover {
  color: #0d2c4a;
}
nav .menu {
  list-style: none;
  display: flex;
  gap: 32px;
  margin: 0;
  padding: 0;
  align-items: center;
}
nav .menu li {
  position: relative;
}
nav .menu li a {
  color: #1a4e8a;
  text-decoration: none;
  font-size: 1.1rem;
  padding: 10px 18px;
  border-radius: 6px;
  transition: background 0.25s, color 0.25s, box-shadow 0.25s;
  font-weight: 500;
  display: block;
  position: relative;
  overflow: hidden;
}
nav .menu li a::after {
  content: '';
  display: block;
  position: absolute;
  left: 50%;
  bottom: 8px;
  width: 0;
  height: 3px;
  background: linear-gradient(90deg, #1a4e8a 60%, #3a7bd5 100%);
  border-radius: 2px;
  transition: width 0.3s cubic-bezier(.4,0,.2,1), left 0.3s cubic-bezier(.4,0,.2,1);
}
nav .menu li a:hover::after,
nav .menu li a.active::after {
  width: 80%;
  left: 10%;
}
nav .menu li a:hover,
nav .menu li a.active {
  background: #e3eaf6;
  color: #0d2c4a;
  box-shadow: 0 2px 8px rgba(58,123,213,0.08);
}

.banner {
  width: 100%;
  overflow: hidden;
  margin-bottom: 32px;
}
.banner img {
  width: 100%;
  height: 320px;
  object-fit: cover;
  display: block;
  border-radius: 0 0 18px 18px;
  box-shadow: 0 4px 24px rgba(26,78,138,0.08);
}

@media (max-width: 900px) {
  .container {
    flex-direction: column;
    height: auto;
    padding: 12px;
    gap: 10px;
  }
  nav .menu {
    gap: 16px;
  }
  .logo a {
    font-size: 1.5rem;
  }
  .banner img {
    height: 160px;
  }
}

@media (max-width: 600px) {
  nav .menu {
    flex-direction: column;
    gap: 8px;
    align-items: flex-start;
    width: 100%;
    background: #fff;
    box-shadow: 0 2px 8px rgba(26,78,138,0.04);
    border-radius: 0 0 12px 12px;
    padding: 10px 0;
  }
  .container {
    padding: 6px;
  }
  .banner img {
    height: 100px;
  }
}