.col-md-6{
  padding: 1em;
  text-align:center;
}

.Grafica{
  width: 100%;
  height: 100%;
  margin:0px auto;
}

 @media only screen and (max-width: 700px) {
   .Grafica{
     width: 100%;
     margin:0px auto;
   }
 }