body {
  font-family: "Gloria Hallelujah";
  height: 100vh;
  width: 100vw;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: white;
  transition: background .5s ease 0s;
}

 .isHidden {
   font-family: "Impact";
   background-color: red;
}