Is there a way to make Firefox display pages in "night mode" like many other apps?

If I read the news at night in my bed in the dark it is BLINDING, not to mention the fact I am burning up my android battery life. Most book reader apps and such have a "night mode" which changes white pages to black with white letters. I looked for addons that do that and they all said "not available for Firefox Android". Seems like it would be more needed for a phone than for a laptop. ... How can I do this? Is it being developed?