# `omena-cascade`
Cascade-formal substrate for the Omena CSS track.
This crate owns the public model for cascade ordering, specificity, static
cascade outcomes, cascade proofs, selector-match witnesses, generic winner
selection, and custom-property substitution. `omena-semantic` consumes this
crate for design-token cascade ranking and selector-context witnesses so
cascade order does not stay duplicated in semantic consumers.
Selector matching is intentionally three-valued. The current witness supports
selector lists and simple compound selectors directly, reports exact misses for
concrete signatures, and returns `Maybe` for unsupported selectors or inexact
abstract element signatures instead of pretending to be a full browser selector
engine.
The crate also exposes a hand-authored conformance seed corpus for the cascade
ordering model. That corpus covers source order, specificity,
origin/importance level, layer rank, scope proximity, and missing-property
inheritance. It is not a replacement for the full WPT `css/css-cascade`
corpus. Separate generated ordering-axis and invariant self-checks exercise the
model broadly, but derive expectations from the same implementation and are
therefore not conformance or regression evidence. A full external WPT mirror
remains a later conformance target.
Transform proof helpers live here as well. `@supports` static evaluation uses an
explicit modern-browser assumption witness, and `@scope` / `@layer` flattening
helpers reject candidates unless the caller can provide the closed-world
cascade conditions needed to erase scope proximity or layer rank.