Instead, any author is allowed to invent _any_ property, so long as the property name begins with a double-dash (--) and you can put anything inside as a value so long as it doesn't break CSS syntax

    a {
      --note:
    
        So you could do this instead and it would be standard CSS, perfectly fine for all people forever!
    
      ;
    }

I still don't think I recommend it, because sure it gets rid of the problem of accidentally breaking CSS namespace, but I still think in most cases sticking comments inside of a property is going to end up confusing people on a team more often than it will help, and there are still some syntax issues and conflicts with your own internal variables that can happen.

But for sure, if you're going to use properties for notes, make them custom properties.

----

Edit: I particularly don't recommend this, but off the top of my head using custom properties you also might be able to rig this up with something like `:before` pseudo-classes to even display some of your CSS comments visibly in the page via `content` or by building style toggles[0] or something.

Again, I feel like this is getting too clever for its own good, but as long as we're playing around...

[0]: https://css-tricks.com/logical-operations-with-css-variables...

    {
      "//": "comment goes here"
    }

For open source, the fake comment won't be removed by CSS compilers, so you end up wasting a little bandwidth.