Pls, don't use all of your layout from spacehey to FR. 😭
They use slightly different stylesheets and only some things are commonly shared.
So, for the footer stripe, that's actually called nav .links on the stylesheet (CSS).
You can change it on your layout with this (inside the style tag, where you have your other colours and tweaks):
footer nav .links {background-color: rgb(6,19,27);}
this is just my example of a dark blue. Use rgba if you want a slight transparency.
But you can use HEX colours too. Example: footer nav .links {background-color: #ff00ff;}
(the colour #ff00ff is a magenta, just change the colours and you're done). :3
.myspace-header .main-nav-wrapper { border-top: #000000; border-bottom: #000000;}
#000000 is black, but you can change it
However, some other stuff is visible still, like a darker blue... Especially the accepts when you hover your cursor over the buttons and some stubborn lines between then (must be another background behind them button/links).
I'm having a bit of a hard time trying to figure this out. But try this help first and tell me if it worked.
EDIT:
.myspace-header {background-color: rgb(13 17 25 / 95%) !important; }
(set the 95% to 0 to make it disappear if you want or change colour)