Another way to accomplish this is to add "MDN" to all CSS and JS searches. For example, "mdn array slice" lands right on the best documentation on array slicing (tested on Google and DuckDuckGo).
If you use Firefox, you can add a search keyword for MDN search, so that you can type "mdn array slice" in the address bar and go straight to MDN without needing DuckDuckGo to redirect you.
My search results for CSS problems are so much better now that MDN is the first result.