Screen went dim?

I was on my macbook pro earlier and the screen randomly went dim. I was just on the internet, not messing with preferences or anything. The computer was still on though because I could still see with a flashlight and everything was still working. I tried restarting it, but it was still the same. What could it be? what can I try? Thanks!

Is your battery low?

sounds like Backlight or inverter might be going....