How To Get The Effect Of Grid Layout's Grid-template-columns With A Variable Number Of Columns?

I have a div containing a variable number of children. This code is generated and I can't modify it. So with only CSS I need to display divs in a table with two rows: The first ro

Solution 1:

Flexbox can do what I think you are after

.parent {
  display: flex;
  flex-wrap: wrap;
  margin-top: 1em;
}

.child {
  flex: 1;
  padding: .25em0;
  color:white;
  font-size:1.25em;
}

.child:nth-child(1) {
  flex: 10100%;
}

Test with 3 children
<divclass="parent"style="background-color:yellow;"><divclass="child"style="background-color:red;">1</div><divclass="child"style="background-color:blue;">2</div><divclass="child"style="background-color:green;">3</div></div>
Test with 4 children
<divclass="parent"style="background-color:yellow;"><divclass="child"style="background-color:red;">1</div><divclass="child"style="background-color:blue;">2</div><divclass="child"style="background-color:green;">3</div><divclass="child"style="background-color:orange;">4</div></div>
Test with 5 children
<divclass="parent"style="background-color:yellow;"><divclass="child"style="background-color:red;">1</div><divclass="child"style="background-color:blue;">2</div><divclass="child"style="background-color:green;">3</div><divclass="child"style="background-color:orange;">4</div><divclass="child"style="background-color:purple;">5</div></div>

Solution 2:

EDIT:

I thought this would work:

.parent {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: 1fr 1fr;
    grid-auto-columns: 1fr;
}

.child:first-child {
  grid-row: 1;
  grid-column: 1 / -1;
}

.child:not(:first-child) {
  grid-row: 2;
}

However, it seems that grid-column: 1 / -1 does not work for auto-columns. That is very unfortunate. Therefore, the best route here would be to use flexbox, as already pointed out.

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Previous answer

You should be able to solve that like this:

.parent {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: 1fr 1fr;
    grid-auto-columns: 1fr;
    grid-auto-flow: column;
}

.child:nth-child(1) {
  grid-column: 1/-1;
}

The key there is grid-auto-flow which will establish that any unforeseen elements will be added as extra columns. With grid-auto-columns you can specify the default size of the automatically added columns.