fix(docs-infra): show (and style correctly) the 'No results found' message (#31390)

PR Close #31390

aio/src/app/shared/search-results/search-results.component.html

@@ -26,5 +26,5 @@
 </ng-template>
 
 <ng-template #notFound>
-  <p>{{notFoundMessage}}</p>
+  <p class="not-found">{{notFoundMessage}}</p>
 </ng-template>

aio/src/styles/2-modules/_search-results.scss

@@ -66,6 +66,12 @@ aio-search-results {
       }
     }
 
+    .not-found {
+      color: $white;
+      text-align: center;
+      margin: 16px;
+    }
+
     @media (max-width: 600px) {
       display: block;
     }
@@ -93,6 +99,10 @@ aio-search-results {
           }
         }
       }
+
+      .not-found {
+        color: $darkgray;
+      }
     }
   }
 }