how to strecha flex flexbox code example

Example 1: flex box align items

.container {
  justify-items: center;
}

Example 2: css flexbox syntax

Display: flex 
Flex-direction: row | row-reverse | column | column-reverse
align-self: flex-start | flex-end | center | baseline | stretch
justify-content: start |  center | space-between | space-around | space-evenly