* {margin:0;padding:0;box-sizing:border-box;font-family:"Microsoft YaHei",sans-serif;}
body {color:#333;background:#f9fafc;line-height:1.6;scroll-behavior:smooth;}
a {text-decoration:none;color:inherit;transition:all .3s;}
ul {list-style:none;}
img {max-width:100%;display:block;}
.container {max-width:1200px;margin:0 auto;padding:0 20px;}

.btn {display:inline-block;padding:12px 30px;border-radius:4px;font-weight:500;border:none;cursor:pointer;transition:all .3s;font-size:15px;}
.btn-primary {background:#005588;color:#fff;}
.btn-primary:hover {background:#003d66;transform:translateY(-2px);box-shadow:0 4px 12px rgba(0,85,136,.2);}
.btn-secondary {background:#fff;color:#005588;border:1px solid #005588;margin-left:15px;}
.btn-secondary:hover {background:#f1f5f9;transform:translateY(-2px);}
.btn-card {padding:8px 20px;font-size:14px;margin-top:10px;}

.section-padding {padding:100px 0;}
.section-title {text-align:center;margin-bottom:80px;}
.section-title h2 {font-size:36px;color:#005588;margin-bottom:20px;}
.section-title p {font-size:16px;color:#666;max-width:700px;margin:0 auto;}
.title-line {width:80px;height:3px;background:#005588;margin:20px auto;border-radius:2px;}
.img-responsive {width:100%;height:auto;}
.required {color:#f56c6c;}

.back-to-top {position:fixed;bottom:30px;right:30px;width:45px;height:45px;background:#005588;color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;opacity:0;visibility:hidden;transition:all .3s;z-index:999;}
.back-to-top.show {opacity:1;visibility:visible;}

header {background:#fff;box-shadow:0 2px 8px rgba(0,0,0,.08);position:sticky;top:0;z-index:999;}
.navbar {display:flex;justify-content:space-between;align-items:center;height:80px;}
.logo {display:flex;align-items:center;gap:8px;}
.nav-menu {
    display: flex;
    flex-direction: row;
    list-style: none;
    margin: 0;
    padding: 0;
}
.nav-menu li {
    margin-right: 20px;
}