Styling elements.

frontend/src/app/components/header/header.component.scss

@@ -192,10 +192,10 @@ app-side-menu {
         }
 
         &.disconnection {
-            color: red;
+            color: #D50000;
 
             &:hover {
-                background-color: red;
+                background-color: #E53935;
                 color: white;
             }
         }