Want to have an easier time reading webpages? Try Blackout. This great extension for Firefox will dim the proverbial lights on Firefox to make reading webpages a lot easier. A white background with black text can be really hard on your eyes after a while. This add-on flips those colors for easier reading.
Here is a little more about Blackout from the add-on developer:
If you are browsing in a dark environment, then it is very bad for your eyes to read pages with white background. This plugin helps you by turning the webpage to a dark color scheme. The “Stay in the dark” function enables you to automatically darken the page when you click on a link and the page loads. Links and headers gets different color then text.
Want to learn more? You can pick up Blackout from the Firefox Add-on website.