What is external CSS?

External CSS refers to styles defined in a separate file that is linked to one or more HTML documents. This approach allows for better organization and maintainability of code since all styling can be managed in a single file rather than having it embedded within each HTML document. When a browser renders an HTML document, it can read the linked CSS file, applying the styles as specified to the elements throughout the page.

Using external CSS has several advantages. It reduces duplication of code, leading to smaller file sizes and faster loading times because multiple HTML files can share the same styling rules. Additionally, it simplifies updates to styles—modifying a single CSS file can instantly change the appearance of an entire website, making it much easier to maintain consistent design and make worldwide styling changes when necessary. This separation of structure (HTML) and design (CSS) contributes to cleaner and more efficient web development practices.