Responsive Background for Mobile

I have a responsive website but my background doesn't shows properly with phone (iphone6) i haven't tried with other phones. My background just zooming in my phone and looks terrible wanna make it responsive to fit on mobile screen.My website is www.orangegsm.hu I tried in css with :cover code that's the code what i'm using right now:

#background
{
    background-attachment: fixed;
    background-image: url("../img/bg1.jpg");
    background-position: left top;
    background-repeat: no-repeat;
    background-size: cover;
    min-height: 100%;
    min-width: 100%;
    position: fixed;
    width: 100%;
    z-index: -2;
}

Thanks!