This is just a quick post update that.. yes, I'm aware that not every color combo (on the color selector) works well between the 'dark' and 'light' themes (notably bright colors struggle on the light theme and dark colors struggle on the dark theme). I've been trying to find a good simple compromise..., but it appears I will have to fix this by having different color options (notably using brighter versions of dark colors on dark themes and vise versa) depending on which theme you are viewing, but that's going to require a bit of code re-write on the script associated with that... so it's on the back burner for now. But thanks to those who pointed it out. Progress is slow, but still moving forward ^_^.
The website was originally designed with an 'orange' color on 'dark' theme, so switch it to that if you want the 'default' look.
That said, use whatever combo works best for you. That's the purpose of that feature, to allow anyone to tailor it to their desired preference. Eventually, I would like to have actual 'themes' and not just color swaps, but I'm but a simple man and that sounds like a complex task for current me.