This document provides an introduction to HTML5 and CSS. It begins by asking why someone needs to learn HTML5 and CSS, then defines HTML as the language used to write websites and help computers communicate. It explains that HTML defines the content of a web page while CSS defines the style. It provides the basic structure of an HTML page, including the <head>, <body>, and <html> tags. It also gives examples of common tags like <p>, <img>, and <a> and notes that some tags close themselves while others require an ending tag. The document concludes by providing some online resources for learning more about HTML.