I installed anki on my phone, and the colour seems to be extremely bad. I mean I use dark background when I use it on my computer, everything is fine but when I use my phone, light letters always go with light background and vice versa, why? it’s too annoying and difficult to read. Hope you improve it on phone. 
Are you using a notetype with custom CSS (=styling) or just “Basic”?
One reason I can think of is that AnkiDroid doesn’t use the CSS variables of Anki Desktop, so any template that relies exclusively on the desktop variables will look off on AnkiDroid.