How to set the background color of a form with c# gradient?

Question

Windows Forms

You need to set the background color of the form to a gradient. How to do it? There are elements on the form. I found on the Internet ways through gradients to squares or through the Paint property to set a gradient. But then do not repaint the inside of the groupboxes. I need to change exactly the "background" color of the form, which is behind all. Thanks in advance for your reply. Sorry, if it's not very sensibly written, it's still night...