I added that code, nothing has changed what I added is in bold (as seen below my style code)

.background {
margin: 0px;
padding: 0px;
border-top-style: none;
border-right-style: none;
border-bottom-style: none;
border-left-style: none;
margin: 0px;
height: 100%;
width: 100%;
left: 0px;
top: 0px;
right: 0px;
bottom: 0px;
background-repeat: no-repeat;
position: absolute;
overflow: visible;
background-image: url(../background.png);
background-position: left top;
padding: 0px;
z-index: 2;
visibility: visible;
}