feat: update UI components for dark mode support and color scheme changes

- Refactored About, Contact, Gallery, Home, Services pages to enhance dark mode compatibility.
- Changed color schemes from orange to sky for various elements.
- Updated background colors and text colors to improve readability in dark mode.
- Added dark mode configuration to Tailwind CSS.

src/app/components/LanguageSwitcher.tsx

@@ -38,7 +38,7 @@ export function LanguageSwitcher() {
       type="button"
       onClick={() => setLang(other as "en" | "nl")}
       aria-label={t("header.language")}
-      className="flex items-center gap-1 bg-white px-2 py-1 text-sm hover:bg-gray-50"
+      className="flex items-center gap-1 px-2 py-1 text-sm hover:bg-gray-50"
     >
       {other === "en" ? <FlagGB /> : <FlagNL />}
     </button>