Currently there is no in-between API for setting a list of properties to the same value: it’s either all or setting each individual property. It would be nice to have more granular shorthands:

1. Using all, but being able to specify exceptions, perhaps, as subsequent values in the existing syntax (e.g. all: revert-layer not background-color, color).
2. Or being able to be specific about the list of properties you want to set to a value. Mixins likely solve this case, though it likely doesn’t do much to change the authoring experience for a single use (i.e. their benefit would be most seem if one had to do this multiple times in a codebase).

In the Shadow DOM, this would be helpful when exposing shadow parts or for styling slotted content or even the shadow host. Currently, if I want to limit my element’s CSS API, I have to either set each of those properties to !important or set all: revert-layer !important in my unlayered styles, then use custom properties for each property:

/* These styles are in a shadow root */

[part="button"] {
  @layer styles {
    /* Properties I want a consumer to be able to customize */
    background-color: var(--background-color, SeaGreen);
    color: var(--color, White);
    /* Properties that I need to set that I don’t want a consumer to customize */
    pointer: cursor;
  }
  
  /* Prevent the consumer from using non-custom properties for styling the part */
  all: revert-layer !important;
}

Outside of the Shadow DOM, this is also helpful in a layered stylesheet since one might want to prevent a subsequent layers from styling certain properties on an element. The existing technique to do this is the same one I demonstrated for the Shadow DOM above (I also have an article explaining this technique).