well then, you didnt edit your style.css properly, because what he/she gave you was the correct advice and there is only ONE change from what you have now.
Here it again, with one minor change to set the color.
font-family: georgia,times,'times new roman', serif;
padding: 0 5px;
margin: 0 auto;
background: #fff; bit sets the color to white so that it doesnt blend with the brown.