* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #fff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部导航 */
.header {
    background: #000;
    color: #fff;
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}
.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}
.logo {
    font-size: 24px;
    font-weight: bold;
    color: #fff;
    text-decoration: none;
}
.nav a {
    color: #ccc;
    text-decoration: none;
    margin-left: 30px;
    transition: color 0.3s;
}
.nav a:hover, .nav a.active {
    color: #1890FF;
}
/* 移动端菜单按钮（默认隐藏） */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: white;
    font-size: 24px;
    cursor: pointer;
}
@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }
    .nav {
        display: none;
        width: 100%;
        flex-direction: column;
        background: #000;
        margin-top: 15px;
        border-top: 1px solid #333;
    }
    .nav.show {
        display: flex;
    }
    .nav a {
        margin: 10px 0;
        padding: 8px 0;
        border-bottom: 1px solid #333;
    }
    .header .container {
        position: relative;
    }
    .logo {
        font-size: 20px;
    }
}

/* 英雄区 */
.hero {
    background: linear-gradient(135deg, #000 0%, #1a1a1a 100%);
    color: white;
    padding: 80px 0;
    text-align: center;
}
.hero h1 { font-size: 2.5rem; margin-bottom: 20px; }
.hero p { font-size: 1.2rem; max-width: 800px; margin: 0 auto; opacity: 0.9; }
.btn {
    display: inline-block;
    background: #1890FF;
    color: white;
    padding: 12px 30px;
    border-radius: 30px;
    text-decoration: none;
    margin-top: 30px;
    font-weight: bold;
    transition: background 0.3s;
}
.btn:hover { background: #0c6bdb; }

/* 通用区块 */
.section {
    padding: 60px 0;
}
.section-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 40px;
}
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}
.card {
    background: #f8f9fa;
    border-radius: 12px;
    padding: 30px;
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}
.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}
.card-icon {
    font-size: 48px;
    margin-bottom: 20px;
}
.card h3 { margin-bottom: 15px; }
.card p { color: #666; }

/* 页脚 */
.footer {
    background: #000;
    color: #ccc;
    text-align: center;
    padding: 30px 0;
    margin-top: 60px;
}

/* 响应式 */
@media (max-width: 768px) {
    .hero h1 { font-size: 1.8rem; }
    .section-title { font-size: 1.5rem; }
    .grid { grid-template-columns: 1fr; }
}