.container {
    display: grid;
    grid-template-columns: auto auto auto;
    grid-template-rows: auto auto auto;

    box-sizing: border-box;
    width: 100%;
    height: 100%;
    margin-left: auto;
    margin-right: auto;
    margin-bottom: auto;
    margin-top: auto;
    justify-items: center;
    align-items: center;
}

.item {
    box-sizing: border-box;
    width: auto;
    height: auto;
}