Centering an Entire Form

Here’s a quick CSS snippet used to center an entire form. Replace 2 in #gform_wrapper_2 with the id of your form.

/* keep it mobile friendly by only applying these styles for larger viewports */
@media only screen and (min-width: 641px) {
 body #gform_wrapper_2 { 
  max-width: 50%;
  margin: 0 auto;
 body #gform_wrapper_2 .gfield .ginput_container,
 body #gform_wrapper_2 .gfield .gfield_description,
 body #gform_wrapper_2 div.ginput_complex label,
 body #gform_wrapper_2 input:not([type='radio']):not([type='checkbox']):not([type='submit']), 
 body #gform_wrapper_2 select, 
 body #gform_wrapper_2 textarea { 
 body #gform_wrapper_2 .top_label .gfield .gfield_label {
  text-align: center;
  display: block;
  body #gform_wrapper_2 .gform_footer,
  body #gform_wrapper_2 .gform_page_footer{
    text-align: center;

Reference: Where to Put Your Custom CSS

If using any caching solution, be sure you have flushed the cache and turned it off while making CSS changes.