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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.1em;
    opacity: 0.9;
}

.nav {
    display: flex;
    background: #f8f9fa;
    padding: 0;
    border-bottom: 2px solid #e9ecef;
}

.nav-item {
    flex: 1;
    padding: 15px 20px;
    text-align: center;
    text-decoration: none;
    color: #666;
    transition: all 0.3s;
    border-bottom: 3px solid transparent;
}

.nav-item:hover {
    background: #e9ecef;
    color: #667eea;
}

.nav-item.active {
    color: #667eea;
    border-bottom-color: #667eea;
    font-weight: bold;
}

.main {
    padding: 40px 30px;
    min-height: 500px;
}

.welcome-section {
    text-align: center;
}

.welcome-section h2 {
    font-size: 2em;
    margin-bottom: 20px;
    color: #333;
}

.welcome-section p {
    font-size: 1.1em;
    color: #666;
    margin-bottom: 40px;
}

.feature-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
    margin-top: 40px;
}

.card {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.card-icon {
    font-size: 3em;
    margin-bottom: 20px;
}

.card h3 {
    font-size: 1.5em;
    margin-bottom: 15px;
    color: #333;
}

.card p {
    color: #666;
    margin-bottom: 20px;
    line-height: 1.6;
}

.btn {
    padding: 12px 30px;
    border: none;
    border-radius: 25px;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
}

.footer {
    background: #f8f9fa;
    padding: 20px;
    text-align: center;
    color: #666;
    border-top: 1px solid #e9ecef;
}

/* ÏìӦʽÉè¼Æ */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2em;
    }

    .main {
        padding: 20px 15px;
    }

    .feature-cards {
        grid-template-columns: 1fr;
    }
}