Effective rounded corners using CSS

/* set the image to use and establish the lower-right position */
.cssbox, .cssbox_body, .cssbox_head, .cssbox_head h2{
background: transparent url(yourimage.png) no-repeat bottom right}
 
.cssbox{     
/* intended total box width - padding-right(next) */       
width:335px !important; /* IE Win = width - padding */       
width: 320px;      
/* the gap on the right edge of the image (not content padding) */       
padding-right:15px; /* use to position the box */       
margin:20px auto}      
 
/* set the top-right image */    
.cssbox_head{
background-position:top right;     
/* pull the right image over on top of border */       
margin-right:-15px;
/* right-image-gap + right-inside padding */      
padding-right:40px}      
 
/* set the top-left image */    
.cssbox_head h2{      
background-position:top left;      
margin:0; /* reset main site styles*/      
border:0; /* ditto */ 
/* padding-left = image gap + interior padding ... no padding-right */      
padding:25px 0 15px 40px; 
height:auto !important;
height:1%} /* IE Holly Hack */     
 
/* set the lower-left corner image */   
.cssbox_body{       
background-position:bottom left;       
margin-right:25px; /* interior-padding right */        
padding:15px 0 15px 40px} /* mirror .cssbox_head right/left */

     <div class="cssbox">
      <div class="cssbox_head">
       <h2>This is a header</h2>
      </div>
      <div class="cssbox_body">
       <p>This is for your content.</p>
      </div>
     </div>