<style>.div{
background: #0A0A0A;
float: right;
margin-left: 10px;
width: 500;
height: 50px;
padding: 5px 7px;
text-align: justify;
color: #eee;
border-radius: 4px;
-moz-border-radius: 4px;
-o-border-radius: 4px;
-webkit-border-radius: 4px;
-ms-border-radius: 4px;
-khtml-border-radius: 4px;
}
.div:before{
content: "";
background: #0A0A0A;
width: 40px;
height: 40px;
transform: rotate(-45deg);
-moz-transform: rotate(-45deg);
-o-transform: rotate(-45deg);
-webkit-transform: rotate(-45deg);
-ms-transform: rotate(-45deg);
-khtml-transform: rotate(-45deg);
float: left;
margin: 5px 0px 0px -26px;
z-index: 1;
}
</style>
<div class="div"></div>