Steam Games Question

When you download a game from steam then sign out, will I need to be online to play single-player games?


So If I buy a game on steam I'll need to have an internet connection to play it?

As far as im aware if its a single player game, you can set steam to offline mode and play without a net connection. You will however need steam to be open to play the game.

So I can play games(the single-player portion) without an internet connection, I'll just need to have steam open in offline mode? Sorry If I'm being a noob, I just really need to know.

thats how it was when i last used it, i can say that much. 



Do you know if this works with Origin as well?

origin has an offline mode, aslong as the game is "activated" with your account it will work in offline mode