Large gap between containers on tablet and Mobile

Hi Everyone,
The site linked below has just gone live, and I am fine tuning some of the pages for tablet and mobile.

I am seeing a large gap between the two inner containers on smaller devices!
I have not worked out why I am getting this, checking all settings does not provide me with an obvious reason why!

There are 9 pages that have these calculators, and they have their own CSS for mobile.
Any ideas ? The custom css is provided below for the page linked.
TIA, Dave

@media screen and (max-width: 767px) {
    .VisiCalcClass {
        min-width: 100%;
        min-height:1250px;
        margin:0;
        padding:0;}

                #Budget_Planner { min-height:5000px !important; }
}