Create Improvements-in-editor.css

[viaahmed]

Currently this file is not commented, however changes can be seen by visually comparing in obsidian. Anyway, this file can be used as snippet, if not merged.

[viaahmed]

I wanted to improve some bits, I want to disclose I don't know how ia writer looks, but I found the theme very good. So I thought of contributing instead of creating from scratch. Btw, this is my first ever Github code contribution.