Problems On Css

[sgs]

Sir, I've a css stylesheet and a page to apply the stylesheet, all things are correct. But the problem is, when I load the page the stylesheet also applies to the page correctly, except the "border". The border must to have to fill the full width of device screen horizontally, but the border fills only half of the screen. Here is the files:

http://pastebin.com/XLvqJHbS (CSS File in PHP file)

http://www.sgservices.tk/sgdp/index.php (Index Page)

Please check the files and tell me what's going wrong?