CSS, or Cascading Style Sheets, is a stylesheet language used to define the visual presentation of documents written in markup languages such as HTML or XML. It essentially controls the layout, colors, fonts, and other stylistic elements of a webpage, transforming basic structural content (defined by HTML) into a visually engaging experience.
Key practices for writing effective CSS include focusing on maintainability, scalability, performance, readability, efficiency, and responsiveness. It's also helpful to use naming conventions, consider browser compatibility, and utilize debugging tools. Following these practices leads to better CSS code and improved web experiences