Inject custom css - what is class tag to add an image as a background for the header

I want to add a background image to the header of my form. I have Frankensteined it on this page:

http://www.magnatexpumps.com/replacement-ansi-pumps-parts.html

but want to get it done correctly by adding custom css.

What class tag do I need to edit for the header?

I have tried this:

.form-header {

color: #c9caca;

text-transform: uppercase;

background: #00693e url('http://www.magnatexpumps.com/images/landing-page-form-header-bg.jpg') no-repeat top; padding: 5px 25px 30px 25px;

}

but it is not working.

Hello magnatexforms,

Please use the following custom css code in your form and that should solve your problem:

.form-header {

color: #c9caca;

text-transform: uppercase;

background-image: url('http://www.magnatexpumps.com/images/landing-page-form-header-bg.jpg');

padding: 5px 25px 30px 25px;

height: 63px;

width: 100%;

}

You need to delete the existing ".form-header" code you have in your form and inject the one share above. 

Hope this helps.

Do get back to us if you have any questions.

Thank you!