What do you understand by Stylesheets? How are these useful ?

A style sheet is a file containing formatting guidelines that define the overall look of a document.

Style sheets are useful in the following ways:

1. It helps to separate structure and presentation. The HTML file can include structure tags and style sheet takes care of the presentation of content.
2. Web pages download much faster.
3. Developers have to type less code, and the web pages are shorter and neater.
4. The look of the site is kept consistent throughout all the pages that work off the same style sheet.
5. Updating design and general site maintenance are made much easier.
6. Errors caused by editing multiple HTML pages occur less often.