Not able to change colum width on mobile

Hei guys quick question.
I want to obtain this result:

That’s what i get:

I m not able to do this with my settings and I m not sure why.
I m speaking about mobile. So i created a column with three columns inside with 3 images.
You can see in the pic. I m not able to make the central column smaller than the others.

Here is my site Read-Only: [LINK][1]

Maybe set div (where 3 elements are placed) with position:relative and all 3 elements on position:absolute. Then you could set position (with percents) on a particular position.