#my_content ul {
  padding-left: 10px;
  list-style: none;
  -moz-column-count: 3;
  -moz-column-gap: 10px;
  -webkit-column-count: 3;
  -webkit-column-gap: 10px;
  column-count: 3;
  column-gap: 10px;
}

@media screen and (max-width: 650px) {
  #my_content ul {
    -moz-column-count: 2;
    -webkit-column-count: 2;
    column-count: 2;
  }
}

@media screen and (max-width: 475px) {
  #my_content ul {
    -moz-column-count: 1;
    -webkit-column-count: 1;
    column-count: 1;
  }
}