Update color palette and styles across components for improved visual consistency

- Changed theme color in index.html to a brighter orange for better aesthetics.
- Introduced a modern color palette in styles.scss for enhanced readability and consistency.
- Updated various components (AppFooter, AppNavigation, DialogWidget, etc.) to utilize new color variables, ensuring a cohesive look throughout the application.
- Adjusted button styles and hover effects for improved user interaction feedback.
- Enhanced background colors and text colors for better contrast and visibility.

frontend/src/views/home/NoLoginView.vue

@@ -174,26 +174,26 @@ export default {
 
 .actions>div {
     flex: 1;
-    background-color: #fdf1db;
+    background-color: #FFF4F0;
     align-items: center;
     justify-content: flex-start;
     display: flex;
-    color: #7E471B;
+    color: #5D4037;
     flex-direction: column;
     overflow: auto;
     padding: 0.5rem;
 }
 
 .actions>div>h2 {
-    color: #F9A22C;
+    color: #FF6B35;
 }
 
 .seo-content {
     max-width: 1000px;
     margin: 24px auto 0 auto;
     padding: 0 16px 40px 16px;
-    color: #7E471B;
-    background-color: #fdf1db;
+    color: #5D4037;
+    background-color: #FFF4F0;
     border: 1px solid rgba(0, 0, 0, 0.06);
     border-radius: 4px;
 }