Universal hover/active effect for the button

index.css

.link {
  height: 36px;
  line-height: 36px;
  display: inline-block;
  /* position: relative is required for :after to work correctly */
  position: relative;
  background-color: white;
  color: black;
  border: 1px solid gray;
}

.link.selected {
  background-color: darkgray;
  color: white;
}

/* hover is not added in case of touch screen devices */
/* IE does not support @media hover, so -ms-high-contrast for backward compatibility */
@media (hover: hover), (-ms-high-contrast: none) {
  .link:hover::after {
    content: '\A';
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.1);
    position: absolute;
    top: 0;
    left: 0;
  }
}

/* :active pseudo class should be defined after :hover */
.link:active::after {
  content: '\A';
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.2);
  position: absolute;
  top: 0;
  left: 0;
}