#buttons{
  display: inline-grid;
  grid-template-columns: auto auto auto;
  grid-gap: 10px;
  text-align: center;
  margin: 20px;
  
}
@media only screen and (max-width: 900px) {
  #buttons{
    display: inline-grid;
    grid-template-columns: auto;
    grid-gap: 10px;
    text-align: center;
    margin: 20px;
    
  }
}

/* This is not working. Fix it */
#buttons.div {
  background-color: lightgray;
}
t1{
  font-size: 2em;
  font-weight: bolder;
}
body{
  /*display: grid;*/
  text-align: center;
}