CSS rules for :visited won't work (beside color)?

Question

So I wanted to make a checkmark on each link somebody visited. This is basic CSS but somehow :visited will only accept color and no other rules. I've tested it on newest Chrome and FF on Mac and also on MS Edge 14 - same behavior.

Here is also a codepen for testing

---

<a href="https://gab3.de">gab3.de</a>
<br>
<a href="https://gabrielw.de">gabrielw.de</a>

---

a:visited {
    color: #ccc;
    text-decoration: line-through;
}

a:visited:before {
  content: "\2713 ";
}

---

So what's the problem?

Answer 1

These are the properties that can be changed with :visited:

1. color
2. List item
3. background-color
4. border-color (and its sub-properties)
5. outline-color

The color parts of the fill and stroke properties You can only use :visited to change those properties.

This are due to privacity concerns, as css tricks states on this information: https://css-tricks.com/almanac/selectors/v/visited/