Check out example codes for "vertical divider between my flexbox". It will help you in understanding the concepts better.

Code Example 1

section {
  display: flex;
  flex-direction: row;
  flex: 1;
  margin: 0 -8px;
  align-items: center;
}
section>* {
  margin: 0 8px;
}
.divider {
  width: 2px;
  margin: 6px 0;
  background: blue;
  align-self: stretch;
}
.item {
  flex: 1;
  background: orange;
}

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