Problem: When a web page doesn't have enough content to fit the screen, the footer doesn't stay at the bottom so it ends up looking weird.

Solution: Do the layout using flex columns. In addtion to that either,

• Add flex-grow: 1 to the content area, here it is the section .
  OR
• Add margin-top: auto to the element you you wish for it to always stay at the bottom, here it is footer .