User style examples
Figure 4 shows a DuckDuckGo page. I use this search engine as the default because it has better respect for people. However, I found that the colours and the contrast on its Web pages were not much to my liking. So, I wrote a user CSS for it, remembering to suffix the styles with an ‘!important’ attribute to override the page authors' setting.
For the Wikipedia website, I use the following CSS because its pages are usually text-heavy and take up the entire width of the screen. On big monitors, they can literally be a pain in the neck.