Allow host to override custom properties

[blasten]

I've been working with custom properties and I noticed that a host could not override the custom properties defined by the element. For example:

<style is="x-style">
 html  x-demo{
   --foo: 1px;
   color: red;
}
</style>

Now, imagine x-demo defined a default value for --foo

:host {
   --foo: 2px;
   color: blue;
}
.read-foo {
      /** color is red which is correct **/
    /** but var(--foo) is 2px  **/
}

var(--foo) should be 1px to be compliant with standard css properties.

[masonlouchart]

If I understood, you want define a style on an element but you don't want apply it. The question is, why define a style on the element ? If you allow the Host to ignore the CSS rules you'll never be able to redefine the style of a nested class.

[blasten]

@LM450N I actually commented more about it on #1470. I will close this pull request.

[masonlouchart]

Nice catch ! You're right, the CSS rules should be propagated. Thank you for your explanations.