Changing colour of sidebar links

Hi, Have SemiColon theme with a child theme created.

I’m trying to change the colour of the links and hover colour in the css
Have found the style sheet colors.css
I have copied this into my child theme, and amended
but site isn’t changing.

I see this line, do I need to do something?
/* Don’t forget to bump $colors_css_version for custom colors to work correctly. */