Adjust Split from 50/50 to 70/30

Is there a way to have the split of the screen be 70% -30%?

Right now, we have it as 50%-50%.

I have it on this site: https://flair-designs.com/project/the-womens-building-nonprofit-website-design/

Thanks,

https://www.ads-software.com/plugins/before-after/