Which browser was the first to support Cascading Style Sheets (CSS)?

The first browser credited with supporting Cascading Style Sheets was Internet Explorer 3.0.

CSS was designed to separate a document’s structure from its visual presentation. HTML could describe headings, paragraphs, links, and other content, while CSS provided rules for colors, fonts, spacing, and layout. The first CSS specification, CSS1, was completed in 1996.

Microsoft released Internet Explorer 3.0 that same year with limited CSS support, making it the conventional answer to this historical browser-trivia question. Its implementation was far from complete, and early CSS support across browsers was inconsistent. Internet Explorer 4 and Netscape Communicator 4.x added more capabilities, but both contained significant bugs and omissions.

“Supported CSS” does not mean “fully implemented CSS.” Internet Explorer 5.0 for Macintosh, released in March 2000, is often credited as the first browser with near-complete CSS1 support. This distinction explains why sources may mention different versions when discussing the first CSS browser: IE3 introduced support, while later browsers made CSS substantially more practical for everyday web design.