/* --- 全局变量与重置 --- */
:root {
    --primary-color: #2563eb; /* 科技蓝，可一键换色 */
    --dark-color: #1e293b;
    --light-bg: #f8fafc;
    --text-color: #475569;
    --max-width: 1200px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: "PingFang SC", "Microsoft YaHei", sans-serif; line-height: 1.6; color: var(--text-color); }
a { text-decoration: none; color: inherit; transition: 0.3s; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* --- 导航栏 --- */
.navbar { background: #fff; padding: 15px 0; box-shadow: 0 2px 10px rgba(0,0,0,0.05); position: sticky; top: 0; z-index: 100; }
.nav-container { display: flex; justify-content: space-between; align-items: center; }
.logo { font-size: 1.5rem; font-weight: 800; color: var(--primary-color); }
.nav-links { display: flex; gap: 30px; }
.nav-links a { font-weight: 500; color: var(--dark-color); }
.nav-links a:hover, .nav-links a.active { color: var(--primary-color); }

/* --- 按钮 --- */
.btn { display: inline-block; padding: 12px 30px; background: var(--primary-color); color: #fff; border-radius: 30px; font-weight: 600; border: none; cursor: pointer; }
.btn:hover { background: #1d4ed8; transform: translateY(-2px); }
.btn-outline { background: transparent; border: 2px solid var(--primary-color); color: var(--primary-color); }
.btn-outline:hover { background: var(--primary-color); color: #fff; }

/* --- 首页横幅 --- */
.hero { padding: 100px 0; background: linear-gradient(135deg, #eff6ff 0%, #fff 100%); text-align: center; }
.hero h1 { font-size: 3rem; color: var(--dark-color); margin-bottom: 20px; }
.hero p { font-size: 1.2rem; margin-bottom: 30px; max-width: 600px; margin-left: auto; margin-right: auto; }

/* --- 通用板块 --- */
.section { padding: 80px 0; }
.section-title { text-align: center; margin-bottom: 50px; }
.section-title h2 { font-size: 2rem; color: var(--dark-color); margin-bottom: 10px; }
.section-title p { color: var(--text-color); }

/* --- 服务卡片网格 --- */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 30px; }
.card { background: #fff; padding: 30px; border-radius: 10px; box-shadow: 0 5px 15px rgba(0,0,0,0.05); transition: 0.3s; border: 1px solid #eee; }
.card:hover { transform: translateY(-5px); border-color: var(--primary-color); }
.card-icon { font-size: 2.5rem; margin-bottom: 20px; }
.card h3 { font-size: 1.25rem; color: var(--dark-color); margin-bottom: 10px; }

/* --- 关于/联系布局 --- */
.about-content, .contact-wrapper { display: grid; grid-template-columns: 1fr 1fr; gap: 50px; align-items: center; }
.contact-form input, .contact-form textarea { width: 100%; padding: 15px; margin-bottom: 15px; border: 1px solid #ddd; border-radius: 5px; font-family: inherit; }
.contact-form textarea { height: 150px; resize: vertical; }

/* --- 页脚 --- */
.footer { background: var(--dark-color); color: #94a3b8; padding: 40px 0; text-align: center; margin-top: 50px; }

/* --- 响应式 --- */
@media (max-width: 768px) {
    .hero h1 { font-size: 2rem; }
    .nav-links { gap: 15px; font-size: 0.9rem; }
    .about-content, .contact-wrapper { grid-template-columns: 1fr; }
}