When steak meat has turned brown it doesn't mean it's bad but the steak turning brown just means that it's not as fresh as before.
Fresh Steak should not be brown but it's not unsafe to eat the steak even when it turns brown as long as the steak isn't slimy or doesn't smell bad.
If the steak turns green or any other color then it might be spoiled but you'll usually notice a bad smell to the spoiled steak and other meats if it's really bad and should be thrown out.
But just because the steak turns brown doesn't mean it's bad to eat and it just means that it won't be as flavorful as it would be if it weren't brown.