<human>:  What is the difference between HTML5 and CSS?
<bot>: The main difference between HTML5 and CSS is that HTML5 is a markup language used for structuring and presenting content on the web, while CSS is a styling language used for describing the presentation of content on the web. HTML5 defines the structure and content of a web page, while CSS defines the look and feel of a web page. HTML5 introduces new semantic elements, such as <header>, <article>, and <nav>, which makes it easier to structure HTML documents. CSS on the other hand allows you to alter the appearance and layout of HTML elements by declaring a set of styles that can be applied to HTML elements.