Ensure conditional hover/focus classes override conditional dark mode classes

[dancormier]

Current behavior: When an element has a conditional dark mode class and a conditional hover or focus class, the dark mode styling overrides the hover style.

Desired behavior: Hover/focus styling should apply over dark mode styling when hovering.

This was prompted by an issue encountered with this markup:

<button id="js-dismiss-articles-btn" class="s-btn fc-black-200 bg-black-600 bc-black-300 h:bg-black-700 d:bg-black-900" type="submit">*</button>