fix(scss): case where invisible text on dark button hover/focus
fix(scss): case where invisible text on dark button hover/focus

Affects .dark a .btn :hover/focus

For example, with red button and red link color, led to red button with (invisible) red text on button hover/focus.

gcushen/hugo-academic,gcushen/hugo-academic,gcushen/hugo-academic,gcushen/hugo-academic