* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: #121212;
    color: #e3e3e3;
}

.item {
    background-color:teal;
    height: 2rem;
    width: 2rem;
}

.grid {
    width: 100%;
    height: 250px;
    display: grid;
    gap: 1rem;
    padding-bottom: 2rem;
    background-color: #333;
}

.grid-4 {
    grid-auto-columns: auto;
    justify-items: center;
}

.grid-5 {
    display: grid;
    width: 100%;
    height: 250px;
    grid-template-areas: 
            "a a a"
            "b c c"
            "b c c";
    grid-template-columns: 50px 1fr 50px;
    grid-template-rows: 150px 1fr;
}

.grid-5 > .a {grid-area: a; background-color: orangered;}
.grid-5 > .b {grid-area: b; background-color: lime;}
.grid-5 > .c {grid-area: c; background-color: violet;}


.grid-6 {
    grid: repeat(3, 80px) / auto-flow;
    justify-items: center;
}

.grid-7 {
    grid-auto-flow: row dense;
    justify-items: center;
}