get rid of background on thank you page and limit digits in phone number field

Please help me get rid of the beige background on the thank you page.  

Also, is there a way to limit the number of digits typed into the phone number field (to help avoid typos)?

To remove the background page color, add the following code to your form:

https://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes

.thankyou, #stage.form-all, #stage.form-all > div {

    background-color : transparent !important;

}

To limit the number of digits entered in the phone field, under the options for the field, enable input mask:

thanks.  I turned on the "input mask" and added the css code but the thank you form is still showing a beige background?

I did a test submission to your form and I can see that the thank you page is not a beige background. Here's my screenshot:

Is your form embedded on a website? What color background do you prefer? 

We'll wait for your reply. Thank you.

thanks.  this worked!  it's embedded on my site so that background is now the same color as the site which is beige.