[Feat] Offer two modes: bright and dim

[dmytro-shchurov]

Sceanic was chosen due to dimmed colors. After 20 years in front of a monitor some people need some rest for eyes. Today, after an update, I was surprised of watching vivid, parrot colors. This is not was I meant choosing Sceanic.

I understand, that you needed some fresh look. Please consider offering two subj. modes, or pls continue to distribute the old version as a separate theme.