html {
    font-size: 10px;
}

#central {
    width: 30rem;
    height: 30rem;
    /* Icon sizing to box */
    /* background: no-repeat center url("icon.png"); */
    /* background-size: 50%; */

    /* Gradient box */
    background: radial-gradient(circle, pink, cyan, pink, pink);
    border-radius: 50%;
}

a {
    font-size: 12px;
    line-height: 1;
    padding: 15px;
    position: relative;
    top: 50%;
    left: 33.33%;
}

a:hover {
    outline: 15px solid black;
}