Added "Services" page & refactor layout structure

- Introduced a new Services component with basic setup.
- Updated layout files to ensure consistent global styling references.
- Enhanced Navbar with pathname detection for active link styling.
- Fixed navigation link URL for "Leistungen" in constants.

components/Navbar/DesktopNav.tsx

@@ -1,5 +1,6 @@
 "use client";
 
+import {usePathname} from "next/navigation";
 import {navLinks} from "@/constant/Constant";
 import Link from "next/link";
 import React, {useContext, useEffect, useState} from "react";
@@ -18,6 +19,7 @@ const Nav = ({openNav}: Props) => {
     const [buttonSize, setButtonSize] = useState("md:px-6 md:py-2 px-4 py-1 text-sm");
     const {theme, toggleTheme} = useContext(ThemeContext);
     const colors = themeColors[theme];
+    const pathname = usePathname();
 
     const navColorClass = theme === "dark" || !navBg ? "text-white" : "text-black";
 
@@ -61,8 +63,11 @@ const Nav = ({openNav}: Props) => {
                     {navLinks.map((link) => (
                         <Link href={link.url} key={link.id}>
                             <p
-                                className={`nav_link ${contentSize} ${navColorClass} transition-all duration-300 ease-in-out uppercase font-semibold`}
-                            >
+                                className={`nav_link ${contentSize} uppercase transition-all duration-300 ease-in-out ${
+                                    pathname === link.url
+                                        ? "text-white font-bold"
+                                        : "text-gray-300 font-medium"
+                                }`}>
                                 {link.label}
                             </p>
                         </Link>