This is the lesser rated and used of the two available dark themes for Amazon, but I must say it's the better in my opinion to just "flip on" and go.

The other one is highly customizable and if you can code in CSS that might be your thing. For the rest of us, I feel this is the better option. I am using it on desktop and cannot speak to the mobile version.

Thank you to the developer! I hope you keep this up to date and text legible as Amazon changes it's layout in the future.