.inteflex {
    min-height: 400px;
    display: grid;
    grid-template-columns: 3fr 3fr 3fr 1fr;
    grid-auto-rows: 1fr;
}

#out {
    grid-column-start: 1;
    grid-column-end: 4;
}


.yellow {
    background-color: yellow;
}

input {
    font-size: large;
}