$dropdown-link-hover-color uses color variable instead of $dropdown-link-color
Created by: robinheidrich
If you change the Sass variable $dropdown-link-color, you also have to change $dropdown-link-hover-color, because this variable uses $gray-900 instead of $dropdown-link-color. (Check here)
Currently:
$dropdown-link-color: $gray-900 !default;
$dropdown-link-hover-color: shade-color($gray-900, 10%) !default;
Corrected:
$dropdown-link-color: $gray-900 !default;
$dropdown-link-hover-color: shade-color($dropdown-link-color, 10%) !default;