Starting from Atom v1.13.0, the contents of atom-text-editor elements are no longer encapsulated within a shadow DOM boundary. This means you should stop using :host and ::shadow pseudo-selectors, and prepend all your syntax selectors with syntax--.
and why its necessary:
Automatic translation of selectors will be removed in a few release cycles to minimize startup time. Please, make sure to upgrade the above selectors as soon as possible.
Prevalent in styles/coala.less
and why its necessary: