If you want to align the last item to the grid use the following code:
Grid container
.card-grid {
box-sizing: border-box;
max-height: 100%;
display: flex;
flex-direction: row;
-webkit-box-orient: horizontal;
-webkit-box-direction: normal;
justify-content: space-between;
align-items: stretch;
align-content: stretch;
-webkit-box-align: stretch;
-webkit-box-orient: horizontal;
-webkit-box-direction: normal;
-ms-flex-flow: row wrap;
flex-flow: row wrap;
}
.card-grid:after {
content: "";
flex: 1 1 100%;
max-width: 32%;
}
Item in the grid
.card {
flex: 1 1 100%;
box-sizing: border-box;
-webkit-box-flex: 1;
max-width: 32%;
display: block;
position: relative;
}
The trick is to set the max-width of the item equal to the max-width of the .card-grid:after.