JSFiddle - React, Tailwind, and code Playground

HTML

<a href="https://google.com">google.com</a>
<a href="https://www.tut.by">www.tut.by</a>

CSS

:link {
  outline: 1px dotted blue;
  background-color: white;
  /* The default value of background-color is `transparent`. You need to
     specify a different value, otherwise changes on :visited won't apply. */
}

:visited {
  outline-color: orange;    /* Visited links have an orange outline */
  /* background-color: green;*/  /* Visited links have a green background */
  background-color: rgba(0, 128, 0, 0.5);  /* Visited links have a green background without transparency */
  color: yellow;            /* Visited links have yellow colored text */
}