Center a form

[presupuesto]

Good afternoon, Please, I am trying to center a form so that it appears in the center of the screen. I have them published without using the Fabrik modules.I can in the folder: "custom_css_.php", center it with the margin-left: 250px;, but this solution is not responsive.I use Helix ultimate and Joomla 4.thank you

 

[wezetel]

Basically you can just assign each field element under 'Formatting` the width 'col-sm-12' , which will cover the whole available space. (HTML places elements always left - except RTL).
For the checkbox you need to select under options '1' as value for 'options per row'