/* 通用样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

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

.header {
    text-align: center;
    color: white;
    padding: 40px 20px;
    margin-bottom: 40px;
}

.header h1 {
    font-size: 48px;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    transition: transform 0.3s;
    text-decoration: none;
    color: inherit;
    display: block;
}

.card:hover {
    transform: translateY(-5px);
}

.card-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.card h2 {
    color: #333;
    margin-bottom: 15px;
}

.login-container {
    max-width: 400px;
    margin: 100px auto;
    background: white;
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

.login-container h1 {
    text-align: center;
    margin-bottom: 30px;
    color: #333;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #666;
    font-weight: 600;
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 14px;
}

.btn {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
}

.error {
    color: #dc3545;
    margin-bottom: 15px;
    padding: 10px;
    background: #f8d7da;
    border-radius: 5px;
}