body, html {
  height: 100%;
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;


}

.center {
          text-align: center;
          margin: auto;
          width: 60%;
          border: none;
          padding: 10px;
          border-radius: 5px;
          background-color: #f2f2f2;


        }

@media screen and (max-width: 600px) {
  .center {
    width: 90%;
    display: block;
    margin-bottom: 20px;
  }
}