Variables for button hover+active states
Created by: quasipickle
A bit of a duplicate of #31544 (closed), but that issue seems to be abandoned.
In my opinion, the background color change between normal & hover states on buttons isn't enough to provide visual feedback that the button has been hovered/clicked. Currently I'm re-defining the necessary rules, but it would be nice to be able to use the mixin.
I propose a bunch of new variables to allow us to set the amount by which a colour is tinted or shaded.
$btn-hover-bg-shade-amount: 15%!default;
$btn-hover-bg-tint-amount: 15%!default;
$btn-hover-border-shade-amount: 20%!default;
$btn-hover-border-tint-amount: 10%!default;
$btn-active-bg-shade-amount: 20%!default;
$btn-active-bg-tint-amount: 20%!default;
$btn-active-border-shade-amount: 25%!default;
$btn-active-border-tint-amount: 10%!default;