Fallback alignment

In CSS Box Alignment, a fallback alignment is specified in order to deal with cases where the requested alignment cannot be fulfilled. For example, if you specify justify-content: space-between there must be more than one alignment subject. If there is not, the fallback alignment is used. This is specified per alignment method, as detailed below.

First baseline start Last baseline safe end Baseline start Space-between flex-start (start) Space-around center Space-evenly center Stretch flex-start (start)