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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

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

.captcha-box {
    background: white;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 10px;
    font-size: 24px;
}

.description {
    text-align: center;
    color: #666;
    margin-bottom: 30px;
    font-size: 14px;
    line-height: 1.5;
}

.captcha-image-container {
    position: relative;
    margin-bottom: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
}

#captchaImage {
    border: 2px solid #e0e0e0;
    border-radius: 6px;
    padding: 15px;
    background: #f5f5f5;
    width: 400px;
    height: 150px;
    object-fit: contain;
}

.refresh-btn {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: #667eea;
    color: white;
    border: none;
    border-radius: 50%;
    width: 36px;
    height: 36px;
    cursor: pointer;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.3s;
}

.refresh-btn:hover {
    background: #5568d3;
}

#captchaForm {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

#captchaInput {
    padding: 12px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 6px;
    font-size: 16px;
    text-transform: uppercase;
    letter-spacing: 2px;
    text-align: center;
    transition: border-color 0.3s;
}

#captchaInput:focus {
    outline: none;
    border-color: #667eea;
}

#submitBtn {
    padding: 12px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s;
}

#submitBtn:hover:not(:disabled) {
    background: #5568d3;
}

#submitBtn:disabled {
    background: #ccc;
    cursor: not-allowed;
}

.error-message {
    color: #e74c3c;
    text-align: center;
    font-size: 14px;
    margin-top: 10px;
    display: none;
}

.success-message {
    color: #27ae60;
    text-align: center;
    font-size: 14px;
    margin-top: 10px;
    display: none;
}

@media (max-width: 480px) {
    .captcha-box {
        padding: 30px 20px;
    }
    
    h1 {
        font-size: 20px;
    }
}