#1 Enhance transaction management UI with form validation, loading states, and improved error handling

src/styles/global.css

@@ -232,3 +232,48 @@ tbody tr:hover {
     padding: 20px;
   }
 }
+
+/* Loading States */
+.loading {
+  opacity: 0.6;
+  pointer-events: none;
+  position: relative;
+}
+
+.loading::after {
+  content: "";
+  position: absolute;
+  top: 50%;
+  left: 50%;
+  width: 1.5em;
+  height: 1.5em;
+  margin: -0.75em 0 0 -0.75em;
+  border: 3px solid rgba(0, 123, 255, 0.2);
+  border-top-color: #007bff;
+  border-radius: 50%;
+  animation: spinner 0.6s linear infinite;
+}
+
+@keyframes spinner {
+  to {
+    transform: rotate(360deg);
+  }
+}
+
+.form-submit-btn {
+  position: relative;
+  min-width: 100px;
+}
+
+.form-submit-btn.loading {
+  padding-right: 35px;
+}
+
+.form-submit-btn.loading::after {
+  width: 1em;
+  height: 1em;
+  margin: -0.5em 0 0 0;
+  left: auto;
+  right: 10px;
+  border-width: 2px;
+}