<human>:  What is the difference between HTML and CSS?
<bot>: The main difference between HTML and CSS is that HTML is used to structure and define the content of a web page, while CSS is used to control the presentation and layout of a web page. HTML focuses on elements such as headings, paragraphs, images, and links, while CSS allows for controlling of spacing, fonts, colors, and background images. HTML is used to add semantic structure to a web page, while CSS is used to style the page and create a visually appealing design.