CSS Stylesheet Editing Trouble

See link: https://www.datafyscience.com/
I am changing my color scheme and am having trouble figuring out the location of a couple sections. For example, to edit the top borders, I use
.tc-header {
border-top-color: #FF9900;
border-bottom-color: #393939;
background: #393939;
}

I cannot figure out how to code these sections:
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*The top menu (search, account, about, contact)
-I want to change the background color from white to orange
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*The page dividers separating posts
-I want to change these lines from white to orange
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*The footer at the bottom of the page (· ? 2014 datafy · Designed by Themes & Co ·)
-I want to change the background color from white to gray
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*The “back to top arrow” at the bottom of the page, displayed on scroll
-I want to change the arrow from blue to orange

Thank you ??