*{margin:0;padding:0;box-sizing:border-box;font-family:Arial,"Microsoft Yahei",sans-serif;}
body{background:#f7f9fc;color:#333;line-height:1.6;}
.container{max-width:1200px;margin:0 auto;padding:0 20px;}

/* 头部导航 */
.site-header{background:#fff;border-bottom:1px solid #eaeaea;padding:18px 0;}
.site-header .container{display:flex;justify-content:space-between;align-items:center;}
.logo a{font-size:22px;font-weight:bold;color:#1a5fb4;text-decoration:none;}
.nav{display:flex;gap:28px;align-items:center;}
.nav a{color:#444;text-decoration:none;font-size:15px;transition:color .2s;}
.nav a:hover{color:#1a5fb4;}
.nav .lang-cn{color:#1a5fb4;border:1px solid #1a5fb4;padding:5px 12px;border-radius:4px;font-size:13px;}

/* 主体内容 */
main{padding:30px 0;min-height:calc(100vh - 280px);}
.page-title{font-size:28px;margin-bottom:24px;color:#222;}
.section-title{font-size:22px;margin:30px 0 18px;color:#222;border-left:4px solid #1a5fb4;padding-left:12px;}

/* 产品分类卡片 */
.product-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin:20px 0;}
.product-card{background:#fff;padding:22px;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,0.06);transition:transform .2s;}
.product-card:hover{transform:translateY(-3px);}
.product-card h3{color:#1a5fb4;margin-bottom:10px;font-size:18px;}

/* 列表页 */
.list-item{background:#fff;padding:20px;border-radius:8px;margin-bottom:16px;box-shadow:0 1px 6px rgba(0,0,0,0.05);}
.list-item h3{margin-bottom:8px;}
.list-item h3 a{color:#222;text-decoration:none;}
.list-item h3 a:hover{color:#1a5fb4;}
.list-item .meta{color:#666;font-size:14px;margin-bottom:8px;}
.list-item .desc{color:#555;}

/* 详情页 */
.detail-box{background:#fff;padding:30px;border-radius:8px;box-shadow:0 2px 10px rgba(0,0,0,0.06);}
.detail-box h1{font-size:28px;margin-bottom:20px;color:#222;}
.detail-info{margin:15px 0;font-size:16px;}
.detail-info strong{display:inline-block;width:140px;color:#555;}
.detail-content{margin-top:20px;line-height:1.8;}
.back-btn{display:inline-block;margin-top:25px;color:#1a5fb4;text-decoration:none;}
.back-btn:hover{text-decoration:underline;}

/* 计算器 */
.calc-box{max-width:660px;margin:0 auto;background:#fff;padding:30px;border-radius:10px;box-shadow:0 2px 12px rgba(0,0,0,0.06);}
.mode-row{display:flex;gap:12px;margin-bottom:20px;}
.mode-btn{flex:1;padding:10px;border:1px solid #1a5fb4;background:#fff;color:#1a5fb4;border-radius:6px;font-size:15px;cursor:pointer;}
.mode-btn.active{background:#1a5fb4;color:#fff;}
.form-item{margin-bottom:16px;}
.form-item label{display:block;margin-bottom:6px;font-size:15px;}
.form-item input{width:100%;padding:10px 12px;font-size:16px;border:1px solid #ccc;border-radius:6px;}
.calc-btn{width:100%;padding:12px;border:none;background:#1a5fb4;color:#fff;font-size:16px;border-radius:6px;cursor:pointer;}
.calc-result{margin-top:22px;padding:18px;background:#f0f6ff;border-radius:8px;line-height:1.8;}
.panel-reverse{display:none;}

/* 底部 */
.site-footer{background:#2c3e50;color:#bdc3c7;padding:40px 0 0;margin-top:40px;}
.site-footer .container{display:grid;grid-template-columns:2fr 1fr 1fr;gap:30px;}
.site-footer h3{color:#fff;margin-bottom:15px;font-size:18px;}
.site-footer ul{list-style:none;}
.site-footer ul li{margin-bottom:6px;}
.copyright{border-top:1px solid #34495e;margin-top:30px;padding:15px 0;font-size:13px;text-align:center;}

/* 响应式 */
@media(max-width:768px){
    .product-grid{grid-template-columns:1fr;}
    .site-footer .container{grid-template-columns:1fr;}
    .nav{gap:15px;}
}