Since version 3.5, Opera has supported CSS, and Håkon Wium Lie, one of the inventors of CSS, is the CTO at Opera. In 1998, Opera 3.5 was released, adding Cascading Style Sheets (CSS) support and file upload capability. It was released for multiple operating systems on December 31, 1997. Opera 3 was the first version of Opera with JavaScript support, but Java was still missing. Opera 15 saw the browser being fully rewritten, with this and subsequent releases being based on Blink and Chromium. In February 2013, Opera Software announced that their in-house rendering engine, Presto, would be phased out in favour of WebKit.

Until version 2.0, the Opera browser was called MultiTorg Opera (version 1.0) and had only a limited internal release-although it was demonstrated publicly at the Third International

Opera has undergone extensive changes and improvements, and introduced notable features such as Speed Dial. In 1995, the project branched out into a separate company named Opera Software ASA, with the first publicly available version released in 1996.

The history of the Opera web browser began in 1994 when it was started as a research project at Telenor, the largest Norwegian telecommunications company.

Opera for older mac 10.7.5