A CSS stylesheet is something that defines items on a webpages, or customizes the appearance of HTML codes. For example, I make an opening page that has a header, a paragraph, and a footer, the stylesheet will be able to tell the header what color, font family, font style, and padding it should be. Then the stylesheet will also tell the paragraph where it should be located, the different font color, size, and family it should be that is completely different that the header. An internal sylesheet is when you style definitions in the head section of an HTML document. What is put in this section will define what happens to the body of the document. Although you type in it, the head section is invisible. An external stylesheet is a separate, it’s saved independently on as another file. The advantage of using an external stylesheet over an internal stylesheet is that it is easier to access. In Dreamweaver you can simply go back and forth with the tabs. When you change something on the external and press save all it will apply to the entire document which is nice if you need to make a small chance.