Håkon Wium Lie (born 1965 in Halden, Norway) is a web pioneer, a standards activist, a politician for The Pirate Party of Norway, and, as of 2013, the Chief Technology Officer of Opera Software.He is best known for proposing the concept of Cascading Style Sheets (CSS) while working with Tim Berners-Lee and Robert Cailliau at CERN in 1994.