bootstrap/scss/helpers/_stacks.scss

@layer helpers {
  // scss-docs-start stacks
  .hstack {
    display: flex;
    flex-direction: row;
    align-items: center;
    align-self: stretch;
  }

  .vstack {
    display: flex;
    flex: 1 1 auto;
    flex-direction: column;
    align-self: stretch;
  }
  // scss-docs-end stacks
}