Much like everything in Drupal 8, setting up custom CKEditor styles is actually ridiculously easy, once you know how. Its just not widely documented or particularly obvious from the admin UI. The good news is, everything you need is a few clicks and couple of lines of yml away!
A brief overview of media queries, breakpoints and the basics of the ‘Mobile First’ approach and also some simple tricks for making media queries more friendly
The application of the Bootstrap framework relies on the principle of applying existing Bootstrap CSS classes to HTML mark-up. When building HTML from scratch, the principle and practice is pretty straight forward. Once your Bootstrap library files are in the right place and working, you simply need to add Bootstrap classes to your mark-up as you go. When developing with Drupal, it can be a challenge to 'crowbar' in the Bootstrap classes you need.
For those looking for a reliable, responsive front-end framework to base their website/drupal theme upon, Twitter Bootstrap can be hard to beat. Luckily there is an existing, contributed theme available to take out the hard work of integrating Bootstrap and Drupal... Well nearly all the hard work.
After a bit of Googling 'cloud based IDE', you'll see there's already quite a few choices. In most cases they provide a fully functioning text/code editor with text highlighting support, basic options for uploading, renaming and deleting files, a cloud based LAMP stack, some kind of terminal or command line and a selection of optional 'plugin' tools.