So I have decided that I want to create an application that is accessible offline. I have experience creating websites using html5, css3, and javascript. I researched some of the differences but can not get a straight answer.
My question is :
What software and languages are important/crucial to know and use when building a desktop application that can be used offline but also uses online tools?
For example, Spotify. Do HTML, CSS, and javascript still get used? Does the code still get written in atom? or does everything change?