Updates to the Steam Client have been released. The updates will be applied automatically when your Steam client is restarted. The specific changes include:

Steam Client

• Added Half-Life: Blue Shift game and desktop icon


• Fixed HTML control sometimes drawing incorrect scrollbar


• Updated required driver versions for Source games


• Added support for Half-Life 1: HiDef model pack. To install the model package, click on the install link below while Steam is running:
  steam://installaddon/halflifehd


To uninstall the HD Pack, click on this link:
steam://removeaddon/halflifehd