#custom-property-no-outside-root

Disallow custom properties outside of :root rules.

    a { --foo: 1px; }
/** ↑   ↑
 * These selectors and these types of custom properties */

#Options

#true

The following patterns are considered warnings:

a { --foo: 1px; }
:root, a { --foo: 1px; }

The following patterns are not considered warnings:

:root { --foo: 1px; }