body {
    height: 100%;
    margin:0;
    font-size: 200px;
}

.parent {
    height: 100%;
    width: 100%;
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    grid-template-rows: repeat(6, 1fr);
    grid-column-gap: 0px;
    grid-row-gap: 0px;
    position: absolute;
    overflow: hidden;
}

.div1 { 
    grid-area: 1 / 1 / 3 / 6;     
    overflow: scroll;
}

.div2 {
    grid-area: 1 / 2 / 4 / 4;
    overflow: scroll;
}

.div3 { 
    grid-area: 3 / 1 / 4 / 7;
    overflow: scroll;
}

.div4 { 
    grid-area: 1 / 6 / 7 / 7;
    overflow: scroll;
}

.div5 {
    grid-area: 4 / 5 / 5 / 6;
    overflow: scroll;
}

.div6 {
    grid-area: 4 / 5 / 6 / 8;
    overflow: scroll;
}

.div7 {
    grid-area: 4 / 1 / 6 / 4;
    overflow: scroll;
}

.div8 {
    grid-area: 3 / 3 / 7 / 6;
    overflow: scroll;
}

.div9 {
    grid-area: 6 / 1 / 7 / 5;
    overflow: scroll;
}

.div10 {
    grid-area: 4 / 7 / 7 / 10;
    overflow: scroll;
}

.div11 {
    grid-area: 1 / 9 / 5 / 10;
    overflow: scroll;
}

.div12 {
    grid-area: 1 / 7 / 3 / 11;
    overflow: scroll;
}

.div13 {
    grid-area: 3 / 7 / 6 / 9;
    overflow: scroll;
}

.div14 {
    grid-area: 5 / 8 / 7 / 13;
    overflow: scroll;
}

.div15 {
    grid-area: 3 / 10 / 7 / 12;
    overflow: scroll;
}

.div16 {
    grid-area: 1 / 12 / 6 / 13;
    overflow: scroll;
}

.div17 {
    grid-area: 1 / 10 / 4 / 13;
    overflow: scroll;
}