<!DOCTYPE html><head><style type="text/css">
* {
border: 1px solid black;
}
.grid {
display: grid;
grid-template-rows: 100px 100px 100px;
grid-template-columns: 100px 100px 100px;
grid-template-areas: "a a b" "a a b" "a a b";
}
.a {
grid-area: a / a / a / a;
background-color: red;
}
.b {
grid-area: b / b / b / b;
background-color: blueviolet;
}
</style></head><body><div class="grid"><div class="a">a</div><div class="b">b</div>