Content not sizing to modal window until browser window resize

Content not sizing to modal window until browser window resize

I know I can fix this with jQuery but am at a loss. Hope someone can help!...

How can I trigger a resize on modal load? I think that’s what I need to do since my content isn’t sizing to the modal window unless I manually resize my browser window, only then does it fill it out.

The top image is what it looks like when I first open the modal.
The bottom image is what it should look like but I have to manually resize my browser window for my content to fill in the window. This is what I want as soon as I click the button.

It's using Magnific Popup but am very new to this coding stuff and am getting confused on how to use the callback functions and run my script.




Thanks in advance!