.parent {
display: grid;
grid-template-columns: repeat(8, 100px);
grid-template-rows: repeat(3, 1fr);
grid-column-gap: 15px;
grid-row-gap: 5px;
}

.div1 { grid-area: 1 / 1 / 2 / 2; }
.div2 { grid-area: 1 / 2 / 2 / 3; }
.div3 { grid-area: 1 / 3 / 2 / 4; }
.div4 { grid-area: 1 / 4 / 2 / 5; }
.div5 { grid-area: 1 / 5 / 2 / 6; }
.div6 { grid-area: 1 / 6 / 2 / 7; }
.div7 { grid-area: 1 / 7 / 2 / 8; }
.div8 { grid-area: 1 / 8 / 2 / 9; }
.div9 { grid-area: 2 / 1 / 3 / 2; }
.div10 { grid-area: 2 / 2 / 3 / 3; }
.div11 { grid-area: 2 / 3 / 3 / 4; }
.div12 { grid-area: 2 / 4 / 3 / 5; }
.div13 { grid-area: 2 / 5 / 3 / 6; }
.div14 { grid-area: 2 / 6 / 3 / 7; }
.div15 { grid-area: 2 / 7 / 3 / 8; }
.div16 { grid-area: 2 / 8 / 3 / 9; }
.div17 { grid-area: 3 / 1 / 4 / 2; }
.div18 { grid-area: 3 / 2 / 4 / 3; }
.div19 { grid-area: 3 / 3 / 4 / 4; }
.div20 { grid-area: 3 / 4 / 4 / 5; }
.div21 { grid-area: 3 / 5 / 4 / 6; }
.div22 { grid-area: 3 / 6 / 4 / 7; }
.div23 { grid-area: 3 / 7 / 4 / 8; }
.div24 { grid-area: 3 / 8 / 4 / 9; }