*{margin:0;padding:0;box-sizing:border-box;}
body{font-family:"微软雅黑",sans-serif;color:#333;line-height:1.6;}
header{background:#0f5199;color:white;padding:20px 50px;display:flex;justify-content:space-between;align-items:center;}
.nav a{color:white;margin:0 15px;text-decoration:none;padding:8px 12px;border-radius:4px;}
.nav a.active{background:#ff6600;}
.banner{background:#eef4f9;padding:40px 50px;text-align:center;}
.container{width:1200px;margin:40px auto;padding:0 20px;}
footer{background:#222;color:#aaa;text-align:center;padding:30px;margin-top:60px;}