#contenedor {
             position: relative;
             margin: 0 auto;
             width: 600px;
             height: auto;
            }

#titulo {
         position: relative;
         margin: 0px;
         border: 1px solid #00C;
         font-size: 20px;
         font-weight: bold;     
         text-align: center; 
         background-color: #00C;
         color: #FFF;   
        }

#cuerpo {
         position: relative;
         margin: 10px;
         padding: 10px;
         border: 1px solid #C00;
         width: 300px;
         left: 150px;
         font-size: 16px;         
        }

a {
   text-decoration: none;
  }

a.actual {
          margin: 0px;
          background-color: yellow;         
         }