What is the direct path to the file for main background color?

Can I get assistance with changing the main background color of the theme? I would like it to be changed to better represent our teams and colors. As of now the page preloader shows a blue colored background while transitioning between pages.

That color is the main background color of the theme it seems and I would like to know if someone can instruct me by providing the direct path to the correct file to make a change to the hex or rgb color code. I think the default color hex is #1d2031

I tried to inspect the properties and it just said
html body, html, .se-pre-con (index):410
If that is correct.

Thank you for any assistance!