bug fix for light/dark mode toggle

this will keep it always in the corner of the screen, instead of weirdness when the container is not very tall

src/app/HomePage.js

@@ -252,7 +252,7 @@ function ColorModeToggleButton() {
       icon={colorMode === "light" ? <MoonIcon /> : <SunIcon />}
       onClick={toggleColorMode}
       variant="ghost"
-      position="absolute"
+      position="fixed"
       bottom="3"
       right="3"
     />