changed header to match new theme

src/app/Header.tsx

@@ -16,7 +16,7 @@ const useStyles = makeStyles((theme: Theme) => {
     appBar: {
 			zIndex: theme.zIndex.drawer + 1,
 			backgroundImage: "none", // This prevents de-saturation of header in dark mode
-			backgroundColor: theme.palette.mode === "light" ? "#3b3b3b" : "#272727"
+			backgroundColor: theme.palette.header.main
 		},
 		toolbar: {
 			marginLeft: theme.spacing(0.5),
@@ -128,4 +128,4 @@ export default function Header() {
 			{isMobile && <BottomNavigator setNavOpen={isOpen => {setNavOpen(isOpen)}} sideIsOpen={navOpen} />}
     </>
   )
-}
+}