If you’re serious about coding, or you want to start out with a solid tool to code with, I strongly recommend Coda 2 for Mac. A beautiful User Interface with tabbed navigation, a super sidebar, and a simple layout. The features are outrageous and extensive, with code folding, smart complete, auto indentation, GIT integration, a built-in terminal, iCloud support — to name a few. The features seem to be endless.
I use Coda 2 for all of my courses & tutorials, and if you decide to use Coda 2 as your editor of choice, it would greatly benefit you when taking my courses. The price of the editor weighs in at $75, but it’s worth every penny — in my honest opinion