<style>       
* { margin: 0; padding: 0; }
          body {
          font: 12px Arial, Helvetica, sans-serif;
          text-align: center;
          background-color: #FFF; }

          #outer_wrapper { width: 840px; margin: 0 auto; background:url(wrapper_bg.gif) repeat-y; }
         /* #wrapper { width: 800px; margin: 0 auto; background-color:#FFFFFF; border: 1px #002B5F solid; }*/
          #wrapper { width: 800px; margin: 0 auto; background:url(footer_shadow.gif) repeat-y;border: 1px }
              
          #container_header { background-color: #376B9A; color: #FFFFFF; }
          #container_content { background-color: #FFFFFF; color: #002B5F; }
          #container_footer { background-color: #376B9A; color: #FFFFFF; }
              
          .clr { clear: both; }
          .contenido { padding: 10px; line-height: 1.0; text-align: left;}     
         </style>
<div id="outer_wrapper">
          <div id="wrapper">
          <div id="container_header">
          <div class="contenido">
          Encabezado
          </div>
          </div>
          <div id="container_content">
          <div class="contenido">
          <strong>Contenido</strong>
           cuerpo ejemplo de sombra de fondo a nuestra pagina</p>
          </div>
          </div>
          <div class="clr"></div>
          <div id="container_footer">
          <div class="contenido">
          Pie de pagina
          </div>
          </div>
          </div>
           <img src="footer_shadow.gif" alt="footer"/>
          </div>