.Arial_12 {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
}
.Arial_14 {

	font-family: Arial, Helvetica, sans-serif;
	font-size: 14px;
}
.Arial_30 {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 30px;
}
.Arial_16 {


	font-family: Arial, Helvetica, sans-serif;
	font-size: 16px;
}
.Georgia_14 {
	font-family: Georgia, Arial, Times, serif;
	font-size: 14px;
	color: #76581B;
}
body {
	background-image: url(../images/bg_principal.jpg);
	background-repeat: repeat;
	background-color: #D8CF74;
}
.Georgia_16 {
	font-family: Georgia, Arial, Times, serif;
	font-size: 16px;
	color: #76581B;
}
<style type="text/css">

/* first example */

 /* set background images for corners */
.rbroundbox { background: url(../graphiques/simple_background.gif) repeat; }
.rbtop div  { background: url(../images/simple_top_left.gif) no-repeat top left; }
.rbtop      { background: url(../images/simple_top_right.gif) no-repeat top right; }
.rbbot div  { background: url(../images/simple_bottom_left.gif) no-repeat bottom left; }
.rbbot      { background: url(../images/simple_bottom_right.gif) no-repeat bottom right; }

 /* height and width details */
.rbtop div, .rbtop, .rbbot div, .rbbot {
	width: 100%;
	height: 14px;
	font-size: 1px;
}
.rbcontent  { margin: 0 14px; }
.rbroundbox { width: 20em; margin: auto; }