Flex-box: Align last row to grid

Question

I have a simple flex-box layout with a container like:

.grid {
  display: flex;
  flex-flow: row wrap;
  justify-content: space-between;
}

Answer 1

One technique would be inserting a number of extra elements (as many as the max number of elements you ever expect to have in a row) that are given zero height. Space is still divided, but superfluous rows collapse to nothing:

http://codepen.io/dalgard/pen/Dbnus

body {
  padding: 5%;
}

div {
  overflow: hidden;
  background-color: yellow;
}

ul {
  display: flex;
  flex-wrap: wrap;
  margin: 0 -4px -4px 0;
  list-style: none;
  padding: 0;
}

li {
  flex: 1 0 200px;
  height: 200px;
  border-right: 4px solid black;
  border-bottom: 4px solid black;
  background-color: deeppink;
}
li:empty {
  height: 0;
  border: none;
}

*,
:before,
:after {
  box-sizing: border-box;
}

  

    
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In the future, this may become achievable through using multiple ::after(n).