body {
  display: -ms-flexbox;
  display: flex;
  -ms-flex-direction: column;
  flex-direction: column;
  height: 100vh; /* Use height insted of min-height for IE 10/11. */
}
main {
  /* Prevent shrinking the main area in IE 10/11. */
  -ms-flex-negative: 0;
  flex-shrink: 0;
}
.footer {
  padding: 1rem 0;
  margin-top: auto;
  background-color: black;
  color: white;
}