Whole page turns black after applying the code.

[LuigiCotocea]

The whole page turns black but the effect on the cursor works, any fixes?

This is what i applied -

        window.addEventListener("load", (event) => { new cursoreffects.rainbowCursor(); });
    </script>

[tholman]

I suspect you may be applying a background color to all canvas elements in your css somewhere. You should be able to inspect the page and see where.