Hello. Try adding this code:

<style>

@media (max-width: 479px) {
#imContent {
margin: 0px 20px !important;
}
}

</style>

Add it here:

You might end up with something like this:

You can find a little more information about inserting code here.

Thanks dear Aleksej H.

I did it your way, but in this case side margin of all other pages is also increasing. 

I want it to be applied to the blog pages and not the website pages.

Please guide.

Mandar

Thanks, dear Giancarlo B.

I did it using your suggestion. 

Regards

Mandar

Excellent, I'm pleased, click the green flag on the post that helped you solve it, in this way the problem will be resolved/closed and consequently also useful to other users who will have the same problem, bye.

Sure, dear friend Giancarlo B.

Already clicked a green flag. 

Thank you once again.