body {
}
 .left_floating,
.right_floating {
  position: fixed;
  top: 500px;
  bottom: 0;
  height: 2.5em;
  margin: auto;
  
}

.left_floating {
  left: 0;
  -webkit-transform-origin: 0 50%;
     -moz-transform-origin: 0 50%;
      -ms-transform-origin: 0 50%;
       -o-transform-origin: 0 50%;
          transform-origin: 0 50%;
  -webkit-transform: rotate(-90deg) translate(-50%, 50%);
     -moz-transform: rotate(-90deg) translate(-50%, 50%);
      -ms-transform: rotate(-90deg) translate(-50%, 50%);
       -o-transform: rotate(-90deg) translate(-50%, 50%);
          transform: rotate(-90deg) translate(-50%, 50%);
}

.right_floating {
   right: 0;
   -webkit-transform-origin: 100% 50%;
      -moz-transform-origin: 100% 50%;
       -ms-transform-origin: 100% 50%;
        -o-transform-origin: 100% 50%;
           transform-origin: 100% 50%;
   -webkit-transform: rotate(90deg) translate(50%, 50%);
      -moz-transform: rotate(90deg) translate(50%, 50%);
       -ms-transform: rotate(90deg) translate(50%, 50%);
        -o-transform: rotate(90deg) translate(50%, 50%);
           transform: rotate(90deg) translate(50%, 50%);
}