Download UltimaDark - The Fastest Dark Mode Extension for Firefox. UltimaDark uses agressive & smart techniques to turn even the sunniest websites into realms of darkness.
Although it works well, this is so experimental, it makes lab rats look like seasoned professionals.
Go ahead, embrace the shadows! 🦇
On my rather old FP3 it spares me a few seconds per page load and the result seems quite comparable to dark reader.