how to center a flexbox code example

Example 1: flexbox align center vertically

.Aligner {
  display: flex;
  align-items: center;
  justify-content: center;
}

.Aligner-item {
  max-width: 50%;
}

.Aligner-item--top {
  align-self: flex-start;
}

.Aligner-item--bottom {
  align-self: flex-end;
}

Example 2: centering with flexbox

/* HORIZONTAL */
justify-content: center;

/* VERTICAL */
align-items: center;

Example 3: center div css flex

section {
  width: 200px;
  border: 1px solid #2d2d2d;
  display: flex;
  justify-content: center;
}