How to justify a single flexbox item (override justify-content)

Question

You can override align-items with align-self for a flex item. I am looking for a way to override justify-content for a flex item.

Answer 1

There doesn't seem to be justify-self, but you can achieve similar result setting appropriate margin to auto¹. E. g. for flex-direction: row (default) you should set margin-right: auto to align the child to the left.

.container {
  height: 100px;
  border: solid 10px skyblue;
  
  display: flex;
  justify-content: flex-end;
}
.block {
  width: 50px;
  background: tomato;
}
.justify-start {
  margin-right: auto;
}

¹ This behaviour is defined by the Flexbox spec.