Cascading Style Sheets or CSS allows many layers of markup to be cascaded to produce a final result separated from the content. This allows for instance easy changing of a sites style without altering html files. It also allows for alternate presentations of the same data, perhaps on a mobile phone, or formatted for printout as a pamphlet.

The cascading nature of the stylesheets allows for replacements, augmentations or minor additions to preceding markup instructions allowing for their revision or removal should it be required.

citations in wikipedia are defined using a superscript tag. The people at wikipedia must know how annoying the endless parade of [citation needed] tags are because they have taken care to not show them when an article is printed. This allows us to distinguish between superscripted text and citation needed superscripted text.

That's lovely but how do I make it go?

Depending on your browser there are a number of ways of implementing a change to the CSS, please select the appropriate browser and follow the instructions.