Hi there,

I do not quite get you here, may I know what u mean by сгыещь custom blocks?

I suppose it can be Section block with 3 columns: 12+6+6+12

Here, you can alter the width in the column block https://take.ms/jSPb9

But there is no way to add background for block?

Do you mean, you want to add background for that particular block? If yes, you can add you own class for that block
https://take.ms/6hcwZ
By adding your own newly created class for this block, you can simply add a new css code to add background in it

Thanks for your cooperation and understanding.