How to center a form using CSS code?

Can you help me to "Center" this form - using this code?  (Right now it is aligned left)

Here's the Code:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

   

     

 

        First Name

       

         

       

     

     

 

        E-mail

       

         

       

     

     

 

       

         

           

              Send

           

         

       

     

     

 

        Should be Empty:

       

     

   

 

 

 

 

 

You only need to inject this CSS code to your form:

.form-all {

    margin-left: auto;

    margin-right: auto;

}

This guide will help you to inject the code: http://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes 

This should be the result: 

FFor further help about generating css form, don't hesitate to contact with us.