#g2 {
padding: 8px;
}

@media (min-width: 840px) {
#g1 {
column-count: 3;
}

#g2 {
column-count: 2;
}
}

@media (min-width: 560px) and (max-width: 839px) {
#g1 {
column-count: 2;
}

#g2 {
column-count: 1;
}
}

@media (max-width: 559px) {
#g1 {
column-count: 1;
}

#g2 {
column-count: 2;
}
}