feat: add 404 page

src/App.jsx

@@ -6,6 +6,7 @@ import * as Sentry from "@sentry/react";
 import { loadConfig } from "actions/global-info";
 import { loadMe } from "actions/users";
 import { initializeWSChannel } from "actions/ws";
+import Button from "components/Button";
 import Footer from "components/Footer";
 import Navbar from "components/Navbar";
 import Home from "pages/Home";
@@ -78,6 +79,22 @@ const LoadingComponent = (
   </div>
 );
 
+const NotFound = () => (
+  <article className="container container--default py-8 lg:py-24">
+    <h1 className="head-alt-base lg:head-alt-lg mb-8">
+      404ka: Tahle stránka tu není
+    </h1>
+    <p className="text-base lg:text-xl mb-8">
+      Dostali jste se na takzvanou „<strong>čtyřystačtyřku</strong>“, což
+      znamená, že stránka, kterou jste se pokusili navštívit, na tomhle webu
+      není.
+    </p>
+    <Button routerTo="/" className="text-base lg:text-xl" hoverActive fullwidth>
+      Přejít na hlavní stránku
+    </Button>
+  </article>
+);
+
 const BaseApp = () => {
   initializeWSChannel.read();
 
@@ -87,6 +104,7 @@ const BaseApp = () => {
       <Switch>
         <Route exact path="/" children={<Home />} />
         <Route exact path="/program" children={<Program />} />
+        <Route component={NotFound} />
       </Switch>
       <Footer />
     </Router>

src/containers/GlobalStats.jsx

@@ -22,7 +22,7 @@ const GlobalStats = () => {
         <strong>{onlineMembers}</strong>{" "}
         <span>
           {onlineMembers === 1 && "člen online"}
-          {onlineMembers > 1 && onlineMembers < 4 && "členové online"}
+          {onlineMembers > 1 && onlineMembers <= 4 && "členové online"}
           {(onlineMembers === 0 || onlineMembers > 4) && "členů online"}
         </span>
       </div>