Change background page/site loading color 7.1

Site URL: https://www.dmbdesignstudio.com/

How do you change the color that flashes before the page loads - currently it is a dark blue site wide, but our new site I am working on is light, bright and airy so the dark blue doesn't match our brand. I have tried this code with the extension to find the section ID but it didn't work. 

[data-section-id="5dd3cc728ca6f6715d3b6571"] .section-background {
    background: red !important;}

https://chrome.google.com/webstore/detail/squarespace-id-finder/igjamfnifnkmecjidfbdipieoaeghcff/related?hl=en

I can't find a way to change it in the site styles either. What are my other options? What can I try?

Thanks in advanced!

You mean top section on homepage?

You can try

[data-section-id="60ec32aae702513746268064"] .section-backgroud {
	background-color: red !important;
}

Right as I stated, I already tried that.