HI jjanicik,
Thank you for your purchase.

Sorry for late response, 

Please note that we have a National holiday in our country from Monday 30th to Wednesday 2nd and because of that, there was a delay in reply to your tickets. Thank you for understanding.

Just add this code in Custom wpDataTables CSS under the "Custom JS AND CSS" in main settings of wpdatatables.

.wpDataTables .wpDataTableFilterSection{
padding:0px !important;
min-height:0 !important;
}
.wpDataTables .wpDataTableFilterSection ul.dropdown-menu li a span{
font-size:20px !important;
}

This will be affected on all tables, but if you want just for specific one then insert this code on page where is that table between the style tag.(<style>Code here</style>)

<style>
.wpDataTables .wpDataTableFilterSection{
padding:0px !important;
min-height:0 !important;
}
.wpDataTables .wpDataTableFilterSection ul.dropdown-menu li a span{
font-size:20px !important;
}
</style>