<human>:  Explain the differences between HTML and CSS.
<bot>: HTML is a markup language used to define the structure of a webpage, while CSS is a styling language used to define the visual appearance of a webpage. HTML is used to describe the content and organization of a webpage, while CSS is used to specify the layout, design, fonts and color schemes. HTML is concerned with the structure and content of a webpage, while CSS is concerned with how a webpage should look.