Update config.mjs

Author: oblomov-dev

docs/.vitepress/config.mjs

@@ -167,10 +167,11 @@ export default defineConfig({
              { text: 'Architecture', link: '/advanced/technical/domain' },
              { text: 'Development Experience', link: '/advanced/technical/dx' },
              { text: 'Cloud Readiness', link: '/advanced/technical/cloud' },
-             { text: 'Deep Dive', link: '/advanced/technical/how_it_all_works' }
-             { text: 'Technology Overview', link: '/advanced/technical/overview' },
-             { text: 'UI5 Freestyle', link: '/advanced/technical/ui5' },
-             { text: 'RAP', link: '/advanced/technical/rap' },
+             { text: 'Deep Dive', link: '/advanced/technical/how_it_all_works' },
+             { text: 'Technology Overview',  collapsed : "false" , items: [
+                 { text: 'UI5 Freestyle', link: '/advanced/technical/ui5' },
+                 { text: 'RAP', link: '/advanced/technical/rap' },
+             ] },  
           ]
            },
          ]