Auto grid sizing allowing nth max in a row in css - css

Question

I am trying to Auto-Sizing Columns in CSS Grid. Like if I have one child-div it will cover full space in mother-div. But if there are multiple child-div it will allow specific number of child-div in a row . Here I am using CSS grid. But I cant do it. Here is my code
<div class="mother-div">
<div class="child-div>
</div>
<div class="child-div>
</div>
</div>
css
.child-div {
background-color: #257790;
height: 100px;
width: 100%;
}
.mother-div {
display: grid;
grid-template-columns: 1fr 1fr 1fr 1fr 1fr;
grid-gap: 1em;
}

Answer 1

What you are looking is almost automatic, grid will behave like this almost out of the box.
You only need to set grid-auto-flow to the direction that you want
To limit the number of items per row, you need to set them to a specific column, using nth-child selector
this style:
.child-div:nth-child(5n+1) {
grid-column: 1;
}
selects childs for n values 0, 1, 2, and so on, that in the formula 5n+1 gives values 1, 6, 11, 16, ...
All those children will go to column 1, that matches the requirement for 5 elements per row.
.child-div {
background-color: #257790;
height: 50px;
width: 100%;
}
.child-div:nth-child(5n+1) {
grid-column: 1;
}
.child-div:nth-child(5n+2) {
grid-column: 2;
}
.child-div:nth-child(5n+3) {
grid-column: 3;
}
.child-div:nth-child(5n+4) {
grid-column: 4;
}
.child-div:nth-child(5n) {
grid-column: 5;
}
.mother-div {
margin: 10px;
width: 500px;
border: solid 3px black;
display: grid;
grid-gap: 1em;
grid-auto-flow: column;
}
<div class="mother-div">
<div class="child-div">
</div>
</div>
<div class="mother-div">
<div class="child-div">
</div>
<div class="child-div">
</div>
</div>
<div class="mother-div">
<div class="child-div">1
</div>
<div class="child-div">2
</div>
<div class="child-div">3
</div>
<div class="child-div">4
</div>
<div class="child-div">5
</div>
<div class="child-div">6
</div>
</div>