@Thasaidon & @BetterRed...I can appreciate what you both say. My old eyes are still good and I'm fine with any application that has a white backround during the daytime. But at night I find that the white background really tends to glare and hurts my eyes and dimming it doesn't help much -- makes it difficult to read. That's when I switch my theme to 'Deep Black' background whenever I'm coding in Notepad++ or other apps that support themes.
I've also often wondered why Sigil doesn't support themes like Notepad++. And I'm not moaning about this or complaining or requesting, but such a feature would really be a wonderful addition to Sigil's bow for us old folks who hate that white glare during the daytime. And the youngsters would love it too -- So cool, dude!! etc...