Do you mean the color scheme? It’s called Monokai, and I think it’s widely available among text editors.
Codepen doesn’t do it for you? I find it really easy to do these little challenges and you will use it later on anyway.
If you want to be able to run things locally, you can use something like Atom, GitHub’s text editor. With the HTML preview option it’s fine for web development, and I use a terminal add-on (terminal-plus I think) to run test code that doesn’t use HTML.
Other options instead of CodePen include JSfiddle and JSbin. All three allow you to register accounts and save projects.
Hope that helps!
Try Visual Code Studio! It’s free and Microsoft open-source! It works very well on OS X and Linux also.
Atom, Brackets, code pen, Visual Code Studio, Sublime, the options are endless!
Does my text-editor look appealing to you? You should know it’s Atom with the Seti UI and Seti Syntax Themes. You might like using it as a long term solution for writing code
If you’re referring to it as a web pluggable to let users type code; then codemirror is the one that FCC uses.