@LexGear The answer to your question is, I use the according Jetbrains IDE. Something less, even though not entirely non-commercial (free for private use), would be Sublime Text, which I use to edit HTML and CSS for non-PHP projects. Both are available natively for Linux. I've yet to find an open source text editor that's remotely as capable as one of those.

@wildrikku I miss Atom :(

@LexGear
Then try Pulsar. It's Atom's fork
@wildrikku