Hi Dharmesh,
It would be nice if WordPress implemented some mobile style variations for some of their standard blocks, but they have yet to do so. As a result, the only way to currently do this is to target each block using CSS, and use media queries:
For example:
@media screen and (max-width: 1024px) {
.wp-block-spacer {
height: 50px !important;
}
}
@media screen and (max-width: 768px) {
.wp-block-spacer {
height: 25px !important;
}
}
I hope this helps, thanks!