Parsing RGBA hex codes fails (feature from CSS Color Module 4)

When a stylesheet with RGBA hex codes is parsed, it triggers ERROR-level logs.

Quick proof from an interactive Python session using cssutils==2.15.0:

$ python
Python 3.12.3 (main, Jun 19 2026, 12:46:00) [GCC 13.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cssutils
>>> cssutils.parseString("body { color: #00808080; }")
ERROR   PropertyValue: Missing token for production Choice(ColorValue, Dimension, URIValue, Value, variable, MSValue, CSSCalc, function): ('HASH', '#00808080', 1, 15)
ERROR   No content to parse.
ERROR   PropertyValue: Unknown syntax or no value:  #00808080
ERROR   CSSStyleDeclaration: Syntax Error in Property: color: #00808080
cssutils.css.CSSStyleSheet(href=None, media=None, title=None)

CSS Color Module 4 documents that as a supported syntax (8-digits): https://drafts.csswg.org/css-color/#hex-notation

I guess it's linked to #29 which covers a generic need to implement features from the CSS Color Module 4.

Empieza reproduciendo el problema con cssutils.parseString("body { color: #00808080; }") y sigue la ruta del parser para los valores de color. Comprueba el manejo existente de la notación hexadecimal de CSS Color Module 4; se considera terminado cuando los colores hexadecimales RGBA de 8 dígitos se pueden analizar sin logs de nivel ERROR ni errores de sintaxis de propiedades.