[Feature] Responsive UI

[irshadshalu]

Loved the project. Would be great to have mobile support as most of my writing happens there.

For an initial version, we can have a bottom navbar hidden by default and another panel over it with styling options.

It gets a bit tricky around other features, so a thorough planning might be needed by the project owner.

[thetronjohnson]

@irshadshalu do you have a wireframe in mind? What I had in mind was, just have the basic editor interface + export MD / PDF for mobile view initially to keep things simple