CSS

CSS, which stands for Cascading Style Sheets, is a style sheet language used to describe the presentation of a document written in HTML or XML. It controls the visual appearance of a web page by specifying aspects such as colors, fonts, spacing, and layout.

CSS is crucial for web development as it allows developers to separate the content of a webpage from its design, enabling consistent styling across multiple pages or an entire website. It also provides responsiveness, making websites adaptable to different devices and screen sizes.

The language uses a hierarchical structure that allows for cascading styles, where styles can be inherited or overridden based on specificity. CSS is constantly evolving, with new features and modules being added to enhance its capabilities and keep up with design trends.

For more information on CSS, you can visit the W3C CSS website or refer to resources like CSS Tricks for tutorials and tips.