Need help centering my pages

Hello!

I recently switched my website’s theme to Gridsby. All of my pages stayed intact, but for some reason, my content shifted to the left. I would like for everything to be centered and to take up the entire width of the page.

My galleries had all been created using the plugin “Tiled Galleries Carousel Without Jetpack.” (Gridsby suggests creating individual posts for each image, which are then shown in gallery form, but I’m hoping to be able to keep using my current galleries, not have a million posts and be able to adjust the order of the images shown…)

Is there something in the parent theme that should be changed regarding the max content width? Or is there anything I can include in my Custom CSS that might help?

Thank you!!

The page I need help with: [log in to see the link]