Box not showing up css

[anil595]

My code worked on the W3school's Tryit Editor, but won't work on a browser.Here's my html:\[code\]<div align="center"> <div class id="welcome"> <iframe src="http://www.cartoonnetwork.com/games/adventuretime/righteousquest/game.swf" width="600" height="400" frameborder="0" marginheight="0" scrolling="no"></iframe><br/><br/> <h1>Adventure Time:Righteous Quest</h1> </div></div> \[/code\]And heres my css:\[code\].welcome{ border:1px solid white; margin:0px; color:#000000; background:#ffffff; }\[/code\]Also, I've tried it without the div align and it produced the same results.Thanks in advance!