Disallow duplicate custom properties within declaration blocks.
a { --custom-property: pink; --custom-property: orange; }
/** ↑ ↑
* These duplicated custom properties */
This rule is case-sensitive.
The following patterns are considered problems:
a { --custom-property: pink; --custom-property: orange; }
a { --custom-property: pink; background: orange; --custom-property: orange }
The following patterns are not considered problems:
a { --custom-property: pink; }
a { --custom-property: pink; --cUstOm-prOpErtY: orange; }