Hypertext Markup Language is used to identify the various parts of a web page. Tags are used to classify and mark the beginning and ending of each piece; an opening tag denotes the beginning and a closing tag denotes the ending. For example, a paragraph will have a <p> tag to denote where it begins and a </p> tag to signify the end.
Cascading Style Sheets is the professional standard for styling web pages. There are three types of CSS: inline, internally, and externally. External CSS should be used to set the theme for an entire web site. Internal CSS on a page when it is necessary to override external settings. Inline CSS is used in places where the internal and external style must be overridden.