a file containing only CSS syntax (no document

a separate file to which any web page can link

a separate file where you can declare all the styles that you want to use on your website

a separate text file that can be associated with one or many HTML documents

a separate text file that each page in the web site can link to it in order to receive it's instructions

a simple text file and commonly uses the naming convention

a template/document/file containing style information which can be linked with any number of HTML documents

A cascading style sheet in a file with a .css file name extension. The .css file is comprised solely of style rules in valid .css syntax, without any surrounding HTML tags. By defining styles in one or more external style sheets and linking them to pages in your web, you ensure a consistent appearance throughout those pages. If you change a style in the external style sheet, the change will be reflected in all of the pages linked to that style sheet.