Moved most of addon into SCSS.
Added more of addon.css.
Major refactor in progress. Everything is broken.
More refactoring. ui module works but content is still broken.
More refactoring. Everything seems to work.
Refactoring. Removed old files. Optimized imports. Fixed typography vars. Isolated color vars.
Fixed problem with sagecell lines getting borders.
Merge branch 'feature/refactor' into develop