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

body {
    background-color: antiquewhite;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: Arial, sans-serif;
}

.container {
    width: 90%;
    max-width: 600px;
    border: 1px solid black;
    padding: 30px;
    text-align: center;
    border-radius: 20px;
    background-color: white;
}

.container h2 {
    margin-bottom: 20px;
    font-size: 2rem;
}

.container p {
    margin-bottom: 20px;
    font-size: 1.2rem;
}

.code-container {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-top: 20px;
    flex-wrap: wrap;
}

.code {
    height: 60px;
    width: 50px;
    border: 1px solid black;
    margin: 5px;
    font-size: 2rem;
    text-align: center;
    border-radius: 10px;
}

.code::-webkit-outer-spin-button,
.code::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.code:valid {
    border: 1px solid green;
    box-shadow: 0 0 5px green;
}

/* Media Queries for Responsiveness */
@media (max-width: 768px) {
    .container {
        padding: 20px;
    }

    .container h2 {
        font-size: 1.5rem;
    }

    .container p {
        font-size: 1rem;
    }

    .code {
        height: 50px;
        width: 40px;
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 15px;
    }

    .container h2 {
        font-size: 1.2rem;
    }

    .container p {
        font-size: 0.9rem;
    }

    .code {
        height: 40px;
        width: 30px;
        font-size: 1.2rem;
    }
}