Use :where() for attribute and complex selectors

[alvaromontoro]

Is your feature request related to a problem? Please describe.

Some rules include attribute selectors with the same weight as a class. We need to keep the specificity of those selectors lower so they don't interfere with the user's selectors.

Describe the solution you'd like

Use :where() in the needed selectors.

Describe alternatives you've considered

An alternative would be using :is(), but then the content would still count for specificity.

Additional context

:where() is not supported by IE. This will be a breaking change.