In CSS Box Alignment, a fallback alignment is specified in order to deal with cases where the requested alignment cannot be fullfilled. 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)