There needs to be a source of truth when it comes to colors in projects. That source of truth should be a single file which contains all colors that you will use throughout all of your projects.
The problem with colors is that they have no meaning when used as part of a component. $color-border
means nothing to both the actual color and when misused as a background (because if there is only one definition of a color it must be used in that way)
I think a good way around this is to have all colors defined in a central location and to use SCSS to logically split up the usage of those colors in a more logical way.
Here's an example: