:root {
    --primary-color: #ff4757;
    --primary-dark: #ff3838;
    --secondary-color: #2f3542;
    --light-color: #f1f2f6;
    --text-color: #2f3542;
    --border-color: #ddd;
}

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

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

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

.auth-box {
    background: white;
    border-radius: 15px;
    padding: 40px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.auth-box h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--secondary-color);
    font-size: 1.8rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-color);
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s;
}

.form-group input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(255, 71, 87, 0.1);
}

.captcha-group {
    display: flex;
    gap: 10px;
    align-items: flex-end;
}

.captcha-group input {
    flex: 1;
}

.btn-send-captcha {
    padding: 12px 20px;
    background: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s;
}

.btn-send-captcha:hover:not(:disabled) {
    background: #1e272e;
}

.btn-send-captcha:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-submit {
    width: 100%;
    padding: 14px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 10px;
}

.btn-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(255, 71, 87, 0.3);
}

.auth-footer {
    text-align: center;
    margin-top: 25px;
    padding-top: 25px;
    border-top: 1px solid var(--border-color);
    color: var(--text-color);
}

.auth-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.auth-footer a:hover {
    text-decoration: underline;
}

.alert {
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.alert-danger {
    background: #ffebee;
    color: #c62828;
    border: 1px solid #ffcdd2;
}

.alert-success {
    background: #e8f5e9;
    color: #2e7d32;
    border: 1px solid #c8e6c9;
}

/* 响应式设计 */
@media (max-width: 480px) {
    .auth-box {
        padding: 30px 20px;
    }
    
    .captcha-group {
        flex-direction: column;
    }
}