This is what I want it to look like:

This is what it looks like now:

Currently, the parent has a display of flex, and it's relevant code is:
display: flex;
flex-wrap: wrap;
justify-content: center;
align-items: center;
with the children having the code of:
flex: 0 0 100%;
In a different project I made it work by giving the parent a display of table and the children a display of table-cell and vertical-align: middle. However, using table to position elements isn't a good practise.