Is there a card modal equivalent to the "overlayTheme": "dark" option that you get with sweet-modals?
I’ve worked around it by adding
.v--modal-overlay { background: rgba(0, 0, 0, 0.6); } to the site CSS but if there is a proper options for it that would be neater.
Not really according to the docs for Vue-Sweet-Modal.
But any theme you customize would just be CSS anyways so targeting the mask as you have would be the way to go.
If you wanted to create your own keywords like “light “, “dark” etc I would look at the source code to see how they are implementing it. It may be possible that they were just targeting a specific path of the CSS for that module. If so then you can easily augment that and add your own theme. But again you have to check the source code for that.