style: refine admin dashboard and project management UI with cohesive color palette and improved readability

- Update background colors and text styles for better contrast and legibility.
- Enhance button styles and hover effects for a more modern look.
- Remove unnecessary scaling effects and adjust border styles for consistency.
- Introduce a cohesive design language across components to improve user experience.

app/manage/page.tsx

@@ -276,7 +276,7 @@ const AdminPage = () => {
         >
           <div className="bg-white/80 backdrop-blur-xl rounded-3xl p-8 border border-stone-200 shadow-2xl relative z-10">
             <div className="text-center mb-8">
-              <div className="w-16 h-16 bg-gradient-to-br from-stone-100 to-white rounded-2xl flex items-center justify-center mx-auto mb-6 shadow-sm border border-stone-100">
+              <div className="w-16 h-16 bg-[#f3f1e7] rounded-2xl flex items-center justify-center mx-auto mb-6 shadow-sm border border-stone-100">
                 <Lock className="w-6 h-6 text-stone-600" />
               </div>
               <h1 className="text-2xl font-bold text-stone-900 mb-2 tracking-tight">Admin Access</h1>