adds color themeing support to the site

src/app/navbar/navbar.component.scss

@@ -158,9 +158,24 @@
 }
 
 .btn-donate-nav {
-  @include button-style($accent-orange, $neutral-white, $accent-orange-dark);
+  background: var(--color-accent);
+  color: var(--color-white);
+  border: none;
+  border-radius: $radius-md;
   padding: $spacing-xs $spacing-md;
   font-size: 0.9rem;
+  font-weight: 600;
+  cursor: pointer;
+  transition: background $transition-fast, transform $transition-fast;
+
+  &:hover {
+    background: var(--color-accent-dark);
+    transform: translateY(-1px);
+  }
+
+  &:active {
+    transform: translateY(0);
+  }
 }
 
 // Responsive