Unexpected behavior with class .btn on anchor elements

[Acmion]

Often buttons are used with the anchor tag like this:
<a href="www" class="btn">Click Me</a>

However, buttons of this type will unexpectedly be affected by the styling of at least a:visited.

The visual state of button elements should not change, except by explicit user action.

For example, the "Install Spectre.css" button in the introduction section on https://picturepan2.github.io/spectre/ is affected by this

[Valeriu Paloş]

I think pull request #572 addresses this issue, but unfortunately the project maintainer still hasn't merged it.

[Acmion]

Nice find!