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 a {
  color: white;
}

.footer a:hover {
  color: white;
}

button.a {
  color: white!important;
}