Overriding sass variables for dynamic themes

[cbutler]

I have created a new theme and want to keep the files for dark and light theme options. I plan to implement a toggle for our users. I'm wondering if someone can help explain to me how you're overriding variables like $bodyBgColor between light and dark themes? I've read through the documentation, but I'm a bit confused. For instance, would replacing this variable in _layout_dark.scss and recompiling be a bad idea if you needed to update in the future? I'm a bit new to this. Thank you.