[CSS]justify-content space-between 左寄せ

3列

.parent {
  display : flex;
  flex-wrap : wrap;
  justify-content:space-between;
}
.parent::after{
  content: "";
  display: block;
  width: 30%;
}
.child {
  width: 30%;
}

4列

.parent {
  display : flex;
  flex-wrap : wrap;
  justify-content:space-between;
}
.parent::before{
  content: "";
  display: block;
  width: 20%;
  order: 1;
}
.parent::after{
  content: "";
  display: block;
  width: 20%;
}
.child {
  width: 20%;
}