fix fleet setup styles (#6909)

frontend/components/App/App.tsx

@@ -32,6 +32,8 @@ interface IAppProps {
     | undefined;
 }
 
+const baseClass = "app";
+
 const App = ({ children, location }: IAppProps): JSX.Element => {
   const queryClient = new QueryClient();
   const {
@@ -136,7 +138,6 @@ const App = ({ children, location }: IAppProps): JSX.Element => {
     return <Fleet500 />;
   };
 
-  const wrapperStyles = classnames("wrapper");
   return isLoading ? (
     <Spinner />
   ) : (
@@ -149,7 +150,7 @@ const App = ({ children, location }: IAppProps): JSX.Element => {
                 fallbackRender={renderErrorOverlay}
                 resetKeys={[location?.pathname]}
               >
-                <div className={wrapperStyles}>{children}</div>
+                <div className={baseClass}>{children}</div>
               </ErrorBoundary>
             </NotificationProvider>
           </PolicyProvider>

frontend/components/App/_styles.scss

@@ -0,0 +1,8 @@
+.app {
+  background: $gradients-dark-gradient-vertical;
+  margin: 0;
+
+  & > div {
+      min-height: 100vh;
+  }
+}

frontend/styles/global/_global.scss

@@ -38,11 +38,6 @@ body {
   }
 }
 
-.wrapper,
-.wrapper > div {
-  min-height: 100vh;
-}
-
 h1,
 h2,
 h3 {