* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Microsoft YaHei", sans-serif;
}
body {
    background: #f5f5f5;
    color: #333;
    line-height: 1.6;
}
a {
    text-decoration: none;
    color: #333;
}
.container {
    width: 1200px;
    margin: 0 auto;
    padding: 20px;
}
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #fff;
    padding: 15px 30px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.logo {
    font-size: 24px;
    font-weight: bold;
}
.nav {
    display: flex;
    gap: 20px;
}
.nav a, .nav-item span {
    padding: 10px 15px;
    cursor: pointer;
}
.nav-item {
    position: relative;
}
.nav-item .sub {
    display: none;
    position: absolute;
    top: 40px;
    left: 0;
    background: #fff;
    width: 180px;
    box-shadow: 0 2px 5px #ccc;
}
.nav-item:hover .sub {
    display: block;
}
.nav-item .sub a {
    display: block;
    padding: 10px 15px;
}
.banner {
    background: #2d374b;
    color: #fff;
    padding: 60px 0;
    text-align: center;
}
.footer {
    background: #2d374b;
    color: #fff;
    text-align: center;
    padding: 20px;
    margin-top: 30px;
}
.list, .news-list, .product-list {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin-top: 20px;
}
.item, .news-item, .product-item {
    width: calc(33.33% - 20px);
    background: #fff;
    padding: 15px;
    border-radius: 5px;
    box-shadow: 0 2px 3px rgba(0,0,0,0.05);
}
.content {
    margin-top: 20px;
    font-size: 16px;
    line-height: 1.8;
}