White blank space on bottom of my website

Different browsers react differently to errors in html and css.
Please use: https://validator.w3.org/
Or other validator to scan your site. Fixing the errors may help with your problem.
If fixing these problems requires you to change theme files then you should change to using a child theme.

Significant errors I see include (may other warnings and error are probably of limited impact):

Error: Stray end tag head.
From line 512, column 5; to line 512, column 11

Error: Start tag body seen but an element of the same type was already open.

I check in the firefox also there is the blank space at bottom is there any CSS code to fix this I don’t understand your current solution.

The validator found that your page has errors. One is that there are TWO “body” elements, this is never correct. You need to fix this problem(s), either seek support from your theme author, or create a child theme and fix it yourself.

Changing css is not a solution.

Friend can you solve this issue for me if I give you admin access? I have no expert knowledge on this.

Sorry, forum rules do not permit performing work of this type using the forum.

Your theme’s authors are:

Author: Devsec Solutions
Author URI: https://devsec.pk

Can they help you ?

Yes I am in discussion with them..