Change SimpleForm ContainerPanel width

Hello,

To display some information I have used the control SimpleForm and as I am using a ResponsiveGridLayout, the different 'sections' have an automatic style with a width of 50%, I want to change this default value to be 30% and 70% so I tried this in the onafterrendering event:

$('#__container14--Panel-cont0_0').css("width", "30%");

$('#__container15--Panel-cont0_1').css("width", "70%");

I saw that the div id remains the same so I tried this way but isnt working at all... any idea of how this can be achieved?

Thanks in advance,

Alex.