Bootstrap 3 inline form for Gravity Forms (only tested with 1 input field and 1 submit button)

gf-inline-form.less

/*
 *
 * Bootstrap 3 inline form for Gravity Forms
 *
 * Use with a class assigned to the form
 * or on .gform to affect all Gravity forms
 *
 * Example 1 (affects targeted form class only): .my-form-class { &:extend(.gravity_form_inline all); }
 * 
 * Example 2 (affects all Gravity Forms): .gform { &:extend(.gravity_form_inline all); }
 *
 */

.gravity_form_inline {
	&, &_wrapper {
		label {
			&:extend(.rel);
			top: 1px;
		}
		.gform_body, .gform_footer {
			&:extend(.inline-block);
		}
		.ginput_container {
			&:extend(.form-inline .form-group, .form-group);
			input {
				&:extend(.form-inline .form-control);
			}
		}
	}
}