[css-variables] Another use case for "cascade"

Hi,

Just figured out I would have liked to have “cascade” today in the following 
case:

    button {
        background: #aaa;
        color: black;
    }

    button:hover {
        background: orange;
        color: white;
    }

    <!-- this button won't become orange on hover :( -->
    <button style="background: red; color: white;">...</button><!-- or 
#button_id { ... } -->

vs


    :hover {
        background: var(--hover-background, cascade);
        color: var(--hover-color, cascade);
    }

    button {
        background: #aaa;
        --hover-background: orange;
        color: black;
        --hover-color: white;
    }

    <!-- it will work :-) -->
    <button style="background: red; color: white;">...</button><!-- or 
#button_id { ... } -->

That's it, this is just for the record and possible later references --  
except if you have comments of course!
François

______________________
PS: Yes, I know, I can maybe use "button:hover" and accept only 
"--hover-background" for buttons, for which I know what the fallback should 
be, but that's maybe not the most elegant option, or is it? What if I don't 
want to change the background if no hover-background was specified?