Wired style underlined anchor with a little flare.

highlight.scss

// Variables
$a-highlight: yellow;

// Sass
.highlight-a a {
  background-color: inherit;
  border-bottom: 1px solid $a-highlight;
  box-shadow: inset 0 -4px 0 $a-highlight;
  color: inherit;
  text-decoration: none;
  transition: background-color 2s;
  
  &:hover, &:active {
    background-color: $a-highlight;
    transition: background-color 2s; }
} // .hightlight-a a