/* CSS and CSS3 used to create imageless ribbon effect for Navigation. */

/* =====
.triangle {
     border-color: transparent #7d90a3 transparent transparent;
     border-style: solid;
     border-width: 15px;
     height: 0;
     width: 0;
           }   ======== */

/* CSS code to style the wrapper bubble rectangle */

/* Reset */

html, body, div, span, h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, font, img, ul, li {
	margin: 0;
	padding: 0;
	border: 0;
	outline: 0;
	font-size: 62.5%;
	vertical-align: baseline;
	background: transparent;
                       }

body {
     line-height: 1.5em;
     }
ol, ul {
     list-style: none;
        }
:focus {
	outline: 0;
}

/* // Reset */

body {
	background: url(bck.jpg); 
	font-family: Georgia, Verdana, “Lucida Sans Unicode”, sans-serif;
	font-size: 1em;
	color: #999;
}

h2 {
	font-style: italic;
	font-weight: normal;
	line-height: 1.2em;
}

div#wrapper {
	margin: 50px auto 0px auto; /* centered */
	width: 400px;
}

.bubble {
	clear: both;
	margin: 0px auto;
	width: 350px;
	background: #fff;
	-moz-border-radius: 10px;
  -khtml-border-radius: 10px;
  -webkit-border-radius: 10px;
	-moz-box-shadow: 0px 0px 8px rgba(0,0,0,0.3);
  -khtml-box-shadow: 0px 0px 8px rgba(0,0,0,0.3);
  -webkit-box-shadow: 0px 0px 8px rgba(0,0,0,0.3);
	position: relative;
	z-index: 90; /* the stack order: displayed under ribbon rectangle (100) */
}

.rectangle {
	background: #7f9db9;
	height: 50px;
	width: 380px;
	position: relative;
	left:-15px;
	top: 30px;
	float: left;
	-moz-box-shadow: 0px 0px 4px rgba(0,0,0,0.55);
  -khtml-box-shadow: 0px 0px 4px rgba(0,0,0,0.55);
  -webkit-box-shadow: 0px 0px 4px rgba(0,0,0,0.55);
	z-index: 100; /* the stack order: foreground */
}

.triangle-l {
	border-color: transparent #7d90a3 transparent transparent;
	border-style:solid;
	border-width:15px;
	height:0px;
	width:0px;
	position: relative;
	left: -30px;
	top: 65px;
	z-index: -1; /* displayed under bubble */
}

.triangle-r {
	border-color: transparent transparent transparent #7d90a3;
	border-style:solid;
	border-width:15px;
	height:0px;
	width:0px;
	position: relative;
	left: 350px;
	top: 35px;
	z-index: -1; /* displayed under bubble */
}

.info {
	padding: 60px 25px 35px 25px;
}

.info h2 {
	font-size: 20px;
}

.info p {
	padding-top: 10px;
	font-size: 14px;
	line-height: 22px;
}

.info p a {
	color: #c4591e;
	text-decoration: none;
}

.info p a:hover {
	text-decoration: underline;
}
.rectangle h2 {
	font-size: 30px;
	color: #fff;
	padding-top: 6px;
	text-shadow: 1px 1px 2px rgba(0,0,0,0.2);
	text-align: center;
}

.menu {
	position: relative;
	top:3px;
	left: 50px;
	z-index: 80; /* the stack order: displayed under bubble (90) */
}

.menu ul li {
	-webkit-transform: rotate(-45deg); /* rotate the list item */
	-moz-transform: rotate(-45deg); /* rotate the list item */
	width: 50px;
	overflow: hidden;
	margin: 10px 0px;
	padding: 5px 5px 5px 18px;
	float: left;
	background: #7f9db9;
	text-align: right;
}

.menu ul li a {
	color: #fff;
	text-decoration: none;
	display:block;
}

.menu ul li.l1 {
	background: rgba(131,178,51,0.65);
}

.menu ul li.l1:hover {
	background: rgb(131,178,51);
}

.menu ul li.l2 {
	background: rgba(196,89,30,0.65);
}

.menu ul li.l2:hover {
	background: rgb(196,89,30);
}

.menu ul li.l3 {
	background: rgba(65,117,160,0.65);
}

.menu ul li.l3:hover {
	background: rgb(65,117,160);
}

.menu span {
	margin: 15px 80px 0px 0px;
	float:right;
}
<!-- The HTLM for the Ribbon -->

<div id="wrapper">     
  <div class="menu">
    <ul>
      <li class="l1"><a href="#">CSS3</a></li>
      <li class="l2"><a href="#">is really</a></li>
      <li class="l3"><a href="#">powerful</a></li>
   </ul>
   <span>by PV.M Garage</span>
  </div>

  <div class="bubble"> 
    <div class="rectangle">
    <div class="triangle-l"></div>
    <div class="triangle-r"></div>
      <h2>3D CSS Ribbon</h2>
    </div>
    <div class="info">
      <h2>I Have Used Only CSS, friends!</h2>
      <p>  
         For this tutorial I have used some new properties of the CSS3.
         You can realize a nice 3D effect using only CSS, it's really 
         fantastic.<br />It doesn't work with IE!
      </p>
    </div> 
  </div>
</div>

CSS Ribbon Styles for depth and html for 3d across ribbon

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