People with disabilities, particularly people with low vision, appreciate the ability to specify a user style sheet. In Internet Explorer you can set it up so your style sheet will take precedence over any settings of the current page. Here is an example of a page before applying the user style sheet. It is the HTML Writer's Guild home page.
Here is the same page after applying a simple style sheet with a yellow on black color combination and x-large font size (about 27 pt). Yellow on black is a scheme that is often rewarding to people who have vision loss, but can still read the screen if the contrasts are just right. Not all elements have been handled with the style sheet, so, for example, the headings have the same fonts as in the original.
In order to enable your own style sheet as in the example above, you need to first disable style sheets (see below) and then enable your own. The American Foundation for the Blind web site provides a menu of color settings and font sizes for viewing their site. Those settings are implemented with style sheets. Below is a screen shot of the menu for choosing colors and font sizes, with the choices (120% zoom, Lime Arial text on Maroon background) applied.