Specificity
The CSS scoring of a selector that resolves cascade ties when origin, importance, and layer are equal. Counted as a four-part tuple: inline, ids, classes/attributes/pseudo-classes, type/pseudo-element.
Specificity is computed as a,b,c,d: a = 1 if the rule is in a
style attribute, b counts ids, c counts classes and attribute
selectors and pseudo-classes, d counts element names and
pseudo-elements. The :not() pseudo-class adopts the highest
specificity of its argument; :where() always contributes zero;
:is() and :has() adopt the highest specificity of their
argument list. Cascade Layers reduce the practical importance of
specificity by giving an outer ordering key.