Frontend style refactoring

wwwroot/css/placeholder.css

@@ -0,0 +1,12 @@
+.placeholder-content {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: var(--s4);
+}
+
+.placeholder-icon {
+  font-size: 4em;
+}