Use btn-$variant-color variables for outlined btns

[intellix]

Despite now having the ability to override outline-variant color, it's not actually being used so each are still #fff

I've set $btn-primary-color to #000 but noticed it was still #fff for outlined buttons because the var isn't passed into @mixin button-outline-variant

Related: #20734

[beausmith]

👍 Nice @intellix! I had forgotten about this.

I recall that I hesitated in committing this change because it does have one visual change… and so I committed the smallest change with the goal of getting it merged, then coming back to this… but I got distracted. So, I'm glad you've made this commit!

The hover color for the secondary outline button is currently white, this commit changes it to the $gray-dark color. Arguably, this change of color makes the behavior more consistent to the default button normal and hover states (see below).

Outline buttons

Default:

Hover (before change):

Hover (after change):

While this does contain a visual change… it makes the secondary outline button hover state more visually similar to that of the default secondary button, adding more contrast to the text color vs background color:

Buttons

Default:

Hover:

I approve this change… however it may have minor affect on projects when they upgrade to use this code.