body {
      animation: colorchange 5s infinite;
      -webkit-animation: colorchange 5s infinite;
    }

    @keyframes colorchange
    {
      0%   {background: pink;}
      25%  {background: yellow;}
      50%  {background: pink;}
      75%  {background: yellow;}
      100% {background: pink;}
    }

    @-webkit-keyframes colorchange
    {
     0%   {background: pink;}
      25%  {background: yellow;}
      50%  {background: pink;}
      75%  {background: yellow;}
      100% {background: pink;}
    }


#txt_name{ 
  font-family: "helvetica";
  font-size: 300%; 
  background-color: white;
  color: grey;
  width: 75%;
  height: 100px;

}

.big {
  font-family: "helvetica";
  font-size: 700%;
  color: white;
  margin-top: 40px;
  margin-bottom: 50px;
}
#center{
  margin-top: 0;
  top: 0;
  bottom: 0;
  right: 0;
  left: 0;
  margin: auto;
  position: absolute;
}