* {
    margin: 0;
    padding: 0;
    font-family: Calibri, sans-serif;
}

form {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    margin: auto;
    display: block;
    width: max-content;
    height: max-content;
}

input {
    display: block;
    margin: 10px auto;
    font-size: 25px;
    text-align: center;
    border: 2px solid #000000;
    border-radius: 100vw;
    padding: 0 5px 0 5px;
    width: min(300px, 90vw);
    height: min(50px, 10vh);
}

input[type="submit"] {
    width: calc(min(300px, 90vw) + 10px);
    cursor: pointer;
}