html – How can I remove the horizontal overflow

I'm going to create a sort of gallery that slides horizontally. I've created a template, but I can not find a way to remove the horizontal slider that appears when the window has a width of 1080px. I've tried adding a masked overflow for the x-axis but that does not seem to work.

Gallery's last photo should be slightly cut to the right and hidden.

Violin: https://jsfiddle.net/eLywmvft/