Creating a Google Chrome extension to manipulate DOM in Service Console.
Thanks to Byron Norris for his Style CSS https://gist.github.com/bluegriff/8c871cd93ea3d2aeed9f904fef69102f, this is looking good!
As long as you are using a version of Chrome that supports extensions, you already have everything you need to start writing an extension of your own. You can start by turning on Developer mode.
Click the Chrome menu icon and select Extensions from the Tools menu. Ensure that the "Developer mode" checkbox in the top right-hand corner is checked. Now you can reload extensions, load an unpacked directory of files as if it were a packaged extension, and more.
For a complete tutorial, see https://developer.chrome.com/docs/extensions/mv2/getstarted/.