columns are not displayed correctly

Hi there,

go to Customizer > General and change the Structure to Floats. This will load the Unsemantic grid.

what to use in Flexbox for columns with sections?

what to use in Flexbox for columns with sections?

You may have to write your own CSS for it.

Alternatively, consider using GenerateBlocks and use its Grid Blocks for section with columns instead of using the sections module.

GB is much easier to use as you don't have to code how the column layout would work.

Thanks, writing a few lines in CSS, I have achieved the desired result. Merge block with site header. My site now looks like this https://zaka.biz/

Nice one! Glad you got it sorted. :D