$theme.panel {
  background: transparent;
  
  .panel-background {
    position: absolute;
    left: -15px;
    top: -15px;
    bottom: -15px;
    right: -15px;
    
    @include slices("panel.png", $top: 25, $left: 25, $right: 25, $bottom: 25, $fill: 1 1);
  }
}