*{
    box-sizing: border-box;
}

.grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr 1fr;
}

div {
    width: 100px;
    height: 100px;
}

div div div {
    border: 10px ridge lime;
}

.red {
    background-color: red;
}

.blue {
    background-color: aqua;
}

.brown {
    background-color: rgb(121, 33, 33);
}