[Madin-H23]

Fixes #19.

cssutils.profile.validate('color', 'unset') is False on main, while inherit is accepted:

>>> cssutils.profile.validate('color', 'inherit')
True
>>> cssutils.profile.validate('color', 'unset')
False

The values are validated against the profile regexes, and the CSS-wide keywords only appear in the regexes where they were spelled out per property, so a value such as unset was reported as invalid.

CSS Values 4 defines initial, inherit, unset and revert as valid in place of the value of any property, so this change adds them where the property regexes are compiled:

CSS_WIDE_KEYWORDS = 'inherit|initial|unset|revert'

The per-property definitions are left untouched, and only those four keywords are added, so invalid values stay invalid.

One existing expectation changes as a consequence: an @font-face descriptor rejecting inherit (font-style: inherit) is now valid, since the CSS-wide keywords apply to any property. If you would rather keep the font-face profile strict, say so and I will scope the change.

Verified locally:

• pytest: 625 passed, 43 xfailed
• ruff check and ruff format --check (ruff 0.17.1): clean
• mypy --config-file mypy.ini cssutils: no new findings (the 40 reported errors are pre-existing on main)

🤖 This contribution was drafted with AI assistance; the analysis, the change and the tests are described above so that they can be reviewed.

[Madin-H23]

The tests workflow on this fork PR is waiting in action_required (the first-time-contributor approval that fork PRs need). Could you approve it so the CI runs?

The change is small, and here is the local verification:

• pytest: 625 passed, 43 xfailed
• ruff check and ruff format --check (ruff 0.17.1): clean
• mypy --config-file mypy.ini cssutils: no new findings (the 40 reported errors are pre-existing on main)

The regression is reproducible on main alone: with the tests of this branch applied to the unpatched sources, test_css_wide_keywords fails, because cssutils.profile.validate('color', 'unset') is False there.