.main {
    display: flex;
    align-items: center;
    justify-content: center;
}

form { display: block; }

.otp-pic {
    border: 1px solid gray;
    height: 500px;
    width: 500px;
}

input, button {
    padding: 2rem;
    margin: 0.3rem;
    border-radius: 5px;
    width: 60vw;
    border: 0.5px solid gray;
}

button {
    width: 70vw;
    background: black;
    color: #ebebeb;
    font-size: 1.7rem;
}
.message {
    height: 1.8rem;
    font-size: 1.3rem;
    color: red;
}

@media (min-width: 768px) {
    input { width: 300px; }
    button {
        width: 340px;
        font-size: 1.3rem;
    }
}