After update home page is messed up

Hi,

After updating de home page of my site is messed up.
It is a grid with thumbnails of my messages. After the update my site is displayed as only one colomn, instead of a dynamic width.
Is there a fix for this, or is it possible to downgrade?

I’m using the them Imbalance 2

My site (withe de nextGen Galery dissabled) https://matthijsimmink.com

Thanks

https://www.ads-software.com/plugins/nextgen-gallery/