Do All Elements in the Universe Have Mass?

[Rodrigo Cesar]

Does everything in the Universe has mass? even sub-atomic particles?
I was watching a video on youtube, the title was "How Much Does a Shadow Weigh?", and I came up with this question

 

[e.bar.goum]

Most elementary particles in the standard model have mass - the bosons that carry the strong and electromagnetic force - gluons and photons respectively -- are the only things we know of that don't have a mass.

It then follows that since everything is made of massive particles (except for light), everything has mass.