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

body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.login-container {
    width: 100%;
    max-width: 400px;
    padding: 20px;
}

.login-card {
    background: white;
    border-radius: 15px;
    padding: 40px 30px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.login-card h1 {
    color: #333;
    margin-bottom: 30px;
    font-size: 28px;
    font-weight: 600;
}

.auth-tabs {
    display: flex;
    margin-bottom: 30px;
    border-radius: 8px;
    overflow: hidden;
    border: 2px solid #f0f0f0;
}

.tab-btn {
    flex: 1;
    padding: 12px;
    border: none;
    background: #f8f9fa;
    color: #666;
    cursor: pointer;
    font-size: 16px;
    transition: all 0.3s ease;
}

.tab-btn.active {
    background: #667eea;
    color: white;
}

.tab-btn:hover:not(.active) {
    background: #e9ecef;
}

.auth-form {
    text-align: left;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #333;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e1e5e9;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.auth-btn {
    width: 100%;
    padding: 15px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.auth-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

.auth-btn:active {
    transform: translateY(0);
}

.message {
    margin: 20px 0;
    padding: 12px;
    border-radius: 8px;
    font-weight: 500;
    display: none;
}

.message.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.message.info {
    background: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

.back-link {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #e1e5e9;
}

.back-link a {
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.back-link a:hover {
    color: #764ba2;
    text-decoration: underline;
}

/* 响应式设计 */
@media (max-width: 480px) {
    .login-container {
        padding: 10px;
    }
    
    .login-card {
        padding: 30px 20px;
    }
    
    .login-card h1 {
        font-size: 24px;
    }
}