Move notification bubbles to bottom right with colored backgrounds

- Changed notification position from top-right to bottom-right
- Added colored backgrounds: green for success, red for error, blue for info/warning
- Improved visual distinction between notification types

templates/base.html

@@ -25,7 +25,7 @@
         /* Notification styles */
         .notification-container {
             position: fixed;
-            top: 20px;
+            bottom: 20px;
             right: 20px;
             z-index: 10000;
             max-width: 400px;
@@ -42,10 +42,10 @@
             transform: translateX(0);
             transition: all 0.3s ease;
         }
-        .notification.success { border-left-color: #10b981; }
-        .notification.error { border-left-color: #ef4444; }
-        .notification.info { border-left-color: #3b82f6; }
-        .notification.warning { border-left-color: #f59e0b; }
+        .notification.success { border-left-color: #10b981; background: #d1fae5; }
+        .notification.error { border-left-color: #ef4444; background: #fee2e2; }
+        .notification.info { border-left-color: #3b82f6; background: #dbeafe; }
+        .notification.warning { border-left-color: #f59e0b; background: #fef3c7; }
         .notification.fade-out {
             opacity: 0;
             transform: translateX(100%);