.center {
   position: absolute;
   top: 50%;
   left: 50%;
   width: 500px;
   height: 500px;
   margin-top: -250px; /* Half the height */
   margin-left: -250px; /* Half the width */
}

.left {
   position: absolute;
   top: 50%;
   left: 0%;
   height: 50px;
   margin-top: -25px; /* Half the height */
   margin-left: 20px;
}