This is a red flag that you are trying to use non standard CSS or you are trying to use things that are so bleeding edge that you are requiring even evergreen browsers to have been restarted and updated very recently. Set your target to any CSS that has been around for about a year or so and is based on standards and you shouldn't need to be writing anything different for specific browsers.

I haven't had to target a specific browser for any CSS in years. I honestly don't know what people are trying to do that would require this now days. Grids, flexbox, animations, transitions no issues and don't even need browser prefixes. The only thing that I can think of that still requires a browser prefix in safari is -webkit-backdrop-filter. Maybe I'm just not doing super out there stuff I guess.