Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

Instead of having :root directly in the selector, use a variable that would allow users to change it for what they want. This update has already been done in OUDS Web and should be done also in Boosted to help having a bi-mode OUDS/Boosted in some contexts.

Motivation and context

The reboot scss file contains a :root selector that is not working with web component, since we need a :host selector. And it also make it hard to add a parent class to the boosted build, since we can't have any parent for :root. People working with framework like Angular or React may want to apply this style to their application custom tag name instead of root.