/* Định dạng tổng thể */
body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(to top, #002f7a, #007bff); /* Gradient xanh giống hình */
    margin: 0;
    overflow: hidden;
}

/* Khung CAPTCHA */
.captcha-container {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0px 4px 10px rgba(0, 0, 0, 0.3);
    text-align: center;
    max-width: 400px;
    width: 100%;
    font-size: 20px;
    text-align: center;
    margin: 25px;
    margin-top: -20vh;
}

/* Tiêu đề */
.captcha-container h2 {
    color: white;
    background: linear-gradient(to top, #0047ab, #007bff); /* Gradient chữ */
    padding: 15px;
    border-radius: 10px 10px 0 0;
    margin: -20px -20px 15px -20px;
    font-size: 24px;
}

/* Câu hỏi */
.captcha-container p {
    font-size: 28px;
    font-weight: bold;
    color: #333;
    margin: 20px;
}

/* Ô nhập */
.captcha-container input {
    width: 90%;
    padding: 14px;
    margin: 10px 0;
    border: 2px solid #ddd;
    border-radius: 8px;
    text-align: center;
    font-size: 20px;
}

/* Nút bấm */
.captcha-container button {
    background: #e60000; /* Màu đỏ */
    color: white;
    font-size: 20px;
    padding: 14px 19px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: 0.3s;
}

.captcha-container button:hover {
    background: #cc0000;
}