button {
    width:100%;
    cursor:pointer;
}

.selection-area {
    width:50%;
    margin-left:auto;
    margin-right:auto;
}

.lesson-navigation-grid {
    display:grid;
    grid-template-columns: auto auto auto;
    text-align:center;    
}

.arrow-container {
    font-size: 4rem;
}

.lesson-navigation-link {
    text-decoration:none;
}

/* --------- iphone portrait -----------  */
@media screen and (max-width: 540px) {
    .selection-area {
        width:100%;
        margin:0;
    }
}