#inner_wrapper{
  background-color: #92c9f3;
  background-image: url(../images/mainbackground.png);
  width: 850px;
  float: left;
  margin-top: 20px;
  margin-bottom: 20px;
}

#wrapper {
  width: 850px;
  margin-left: auto;
  margin-right: auto;
}