Every steam game I own requires the steam client to be running while I am playing the game, the games become bricked if I remove steam so this is DRM. I can go into offline mode for most games, but the client must always be there.
Installing the game requires both the steam client and a connection, this is authorizing the install and is DRM.
Installing the game requires both the steam client and a connection, this is authorizing the install and is DRM.