Glossary

Cascade

The CSS algorithm that resolves conflicting declarations into a single computed value per property per element. Considers origin, importance, layer order, specificity, and source order in that sequence.

The cascade is the engine that gives CSS its name. CSS Cascading Level 5 (2022) added the layer dimension between origin and importance, letting authors sequence design-system rules without specificity wars. Within a layer, specificity still resolves ties: id > class/attribute/pseudo-class > element. The !important modifier inverts origin order so user-agent important wins over author important; this is rarely what authors intend.