FR: get mado-heading and other CSS features to work in LP mode

[DudeThatsErin]

It would be awesome if those features worked in LP mode instead of just reading mode. Right now they are useless to me cause I rarely use reading mode. I am always in LP mode.

[hydescarf]

Ah, it's indeed awesome if they also work in LP mode. Those classes were made back then when certain functions of the client weren't implemented yet, so they were only possible in Reading mode.

It should be now possible to implement them in LP mode, but unfortunately, I might not want to devote my time for that. (These repos are actually on maintenance mode, to be honest) :(

I'll leave this up for someone to contribute, or maybe I could be doing this in the future, but there's no guarantee for now.