/* --- 基础重置 --- */
:root {
    --primary-color: #0f172a; /* 深蓝黑背景 */
    --accent-color: #38bdf8;  /* 科技蓝高亮 */
    --text-color: #e2e8f0;    /* 浅灰文字 */
    --white: #ffffff;
    --transition: all 0.3s ease;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Inter', system-ui, sans-serif; background-color: var(--primary-color); color: var(--text-color); line-height: 1.6; }
a { text-decoration: none; color: inherit; transition: var(--transition); }
ul { list-style: none; }

/* --- 导航栏 --- */
header { background: rgba(15, 23, 42, 0.95); padding: 1rem 0; position: fixed; width: 100%; top: 0; z-index: 1000; border-bottom: 1px solid #1e293b; }
.container { width: 90%; max-width: 1200px; margin: 0 auto; }
.nav-content { display: flex; justify-content: space-between; align-items: center; }
.logo { font-size: 1.5rem; font-weight: 800; color: var(--white); letter-spacing: -1px; }
.logo span { color: var(--accent-color); }
nav ul { display: flex; gap: 2rem; }
nav a:hover { color: var(--accent-color); }

/* --- 通用组件 --- */
.btn { display: inline-block; padding: 0.8rem 2rem; background: var(--accent-color); color: var(--primary-color); border-radius: 6px; font-weight: 600; }
.btn:hover { background: #7dd3fc; transform: translateY(-2px); }
.section-title { text-align: center; font-size: 2.5rem; margin-bottom: 3rem; color: var(--white); }

/* --- 首页 Hero --- */
.hero { padding: 160px 0 100px; text-align: center; background: radial-gradient(circle at center, #1e293b 0%, #0f172a 70%); }
.hero h1 { font-size: 3.5rem; margin-bottom: 1.5rem; color: var(--white); line-height: 1.2; }
.hero p { font-size: 1.2rem; max-width: 600px; margin: 0 auto 2rem; opacity: 0.8; }

/* --- 网格布局 --- */
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 2rem; padding: 4rem 0; }
.card { background: #1e293b; padding: 2rem; border-radius: 12px; border: 1px solid #334155; transition: var(--transition); }
.card:hover { transform: translateY(-5px); border-color: var(--accent-color); }
.card h3 { margin-bottom: 1rem; color: var(--white); font-size: 1.5rem; }

/* --- 产品页 --- */
.page-header { padding: 140px 0 60px; text-align: center; }
.product-item { display: flex; gap: 2rem; margin-bottom: 4rem; align-items: center; }
.product-item:nth-child(even) { flex-direction: row-reverse; }
.product-img { flex: 1; border-radius: 12px; overflow: hidden; }
.product-img img { width: 100%; height: auto; display: block; }
.product-info { flex: 1; }
.product-info h2 { font-size: 2rem; margin-bottom: 1rem; color: var(--white); }

/* --- 联系页 --- */
.contact-wrapper { max-width: 800px; margin: 0 auto; padding: 4rem 0; }
.form-group { margin-bottom: 1.5rem; }
input, textarea { width: 100%; padding: 1rem; background: #1e293b; border: 1px solid #334155; color: var(--white); border-radius: 6px; }
input:focus, textarea:focus { outline: none; border-color: var(--accent-color); }

/* --- 页脚 --- */
footer { background: #020617; padding: 3rem 0; text-align: center; border-top: 1px solid #1e293b; margin-top: auto; }

/* --- 响应式 --- */
@media (max-width: 768px) {
    .hero h1 { font-size: 2.5rem; }
    .product-item, .product-item:nth-child(even) { flex-direction: column; }
    nav ul { gap: 1rem; font-size: 0.9rem; }
}