search-engine-optimization/_sass/modules/_links.scss

$link-color: #2980b9;
$link-active-color: lighten($link-color, 10%);
$link-hover-color: darken($link-color, 10%);

a {
  background: transparent;
  border: 0;
  color: $link-color;
  text-decoration: none;
  transition: background-color 0.3s, color 0.3s;

  &:active {
    color: $link-active-color;
  }

  &:focus,
  &:hover {
    color: $link-hover-color;
  }

  &:focus {
    outline: none;
  }
}