feat: improve accessibility of donation button in WelcomeModal

src/components/WelcomeModal.tsx

@@ -394,7 +394,7 @@ const WelcomeModal: Component = (props) => {
       <div class="mt-14 relative flex justify-center items-center gap-10">
         <a
           href="#welcome-patron"
-          class="hidden xl:flex btn btn-sm btn-secondary gap-2 transition-all shadow-lg hover:shadow-lg shadow-purple-300 hover:shadow-purple-500 hover:ring-2 ring-offset-2 ring-purple-500"
+          class="hidden xl:flex btn btn-sm btn-secondary bg-purple-600 border-purple-600 gap-2 transition-all shadow-lg hover:shadow-lg shadow-purple-300 hover:shadow-purple-500 hover:ring-2 ring-offset-2 ring-purple-500"
         >
           <DonationIcon />
           Spenden