sticky-footer.css

body {
  display: grid;

  /* Define three rows. The first and last's height will be automatic and the middle section will fill the rest of the space */
  grid-template-rows: auto 1fr auto;

  /* Each row should fill up 100% of the viewport. Without this, you will get some horizontal scrolling at smaller viewports */
  grid-template-columns: 100%;

  /* The body should be the height of the viewport, or else the footer won't stick to the bottom */
  min-height: 100vh;
}