There are certain rules that apply to attribute specializations.
A specialized attribute has the following characteristics:
- It is specialized from
@props or @base.
- It is declared as a global attribute. Attribute specializations cannot be limited to
specific element types.
- It does not have values or value ranges that are more extensive than those of the
attribute from which it was specialized.
- Its values must be alphanumeric space-delimited values. In generalized form, the values
must conform to the rules for attribute generalization.