Tantek Çelik, of San Francisco, is a computer scientist of Turkish-American descent and was the Chief Technologist at Technorati . He is one of the principal editors of several CSS Specifications. He gained a following during his time at Microsoft (1997-2004), where he worked on the Macintosh version of Internet Explorer . Between 1998 and 2003 he managed a team of software developers that designed and implemented the Tasman rendering engine for Internet Explorer for Mac version 5 . During his time at Microsoft he also served as their alternate representative (1998-2000) and later their representative (2001-2004) to a number of working groups at the World Wide Web Consortium (W3C) , due to this work he is credited on a number of recommendations relating to XHTML and Cascading Style Sheets.