class {
  Ubuntu { image = "$$/icons-nopop/button-ubuntu.png:$$/icons-nopop/button-ubuntu-hover.png" }
  Linux { image = "$$/icons-nopop/button-linux.png:$$/icons-nopop/button-linux-hover.png" }
  MacOSX { image = "$$/icons-nopop/button-osx.png:$$/icons-nopop/button-osx-hover.png" }
  Windows { image = "$$/icons-nopop/button-windows.png:$$/icons-nopop/button-windows-hover.png" }
  Unknown { image = "$$/icons-nopop/button-unknown.png:$$/icons-nopop/button-unknown-hover.png" }
}
