- add flag images for language switcher

- hide messages if room parameter is not given

launch.html

@@ -32,6 +32,9 @@
         top: 16px;
         right: 16px;
         z-index: 100;
+        display: flex;
+        align-items: flex-start;
+        gap: 8px;
       }
 
       .lang-menu {
@@ -78,6 +81,14 @@
         background: #f0f8ff;
       }
 
+      .lang-flag {
+        width: 20px;
+        height: 13px;
+        margin-right: 6px;
+        border-radius: 2px;
+        vertical-align: -2px;
+      }
+
       .card {
         box-sizing: border-box;
         width: min(600px, calc(100% - 32px));
@@ -266,14 +277,18 @@
 
   <body>
     <nav class="navbar">
+      <a class="button secondary" href="https://www.bnvb-ingenieure.de/impressum" target="_blank" rel="noopener noreferrer">
+        Impressum
+      </a>
       <div id="langMenu" class="lang-menu">
         <button id="langButton" class="button secondary" type="button" aria-haspopup="true" aria-expanded="false">
-          English
+          <img id="langFlag" class="lang-flag" src="assets/uk.svg" alt="">
+          <span id="langLabel">English</span>
         </button>
         <div id="langDropdown" class="lang-dropdown">
-          <button type="button" data-lang="en">English</button>
-          <button type="button" data-lang="de">Deutsch</button>
-          <button type="button" data-lang="fr">Français</button>
+          <button type="button" data-lang="en"><img class="lang-flag" src="assets/uk.svg" alt="">English</button>
+          <button type="button" data-lang="de"><img class="lang-flag" src="assets/de.svg" alt="">Deutsch</button>
+          <button type="button" data-lang="fr"><img class="lang-flag" src="assets/fr.svg" alt="">Français</button>
         </div>
       </div>
     </nav>
@@ -881,8 +896,15 @@
         fr: "Français"
       };
 
+      const LANGUAGE_FLAGS = {
+        en: "assets/uk.svg",
+        de: "assets/de.svg",
+        fr: "assets/fr.svg"
+      };
+
       function updateLanguageMenu() {
-        langButton.textContent = LANGUAGE_NAMES[currentLanguage];
+        langFlag.src = LANGUAGE_FLAGS[currentLanguage];
+        langLabel.textContent = LANGUAGE_NAMES[currentLanguage];
 
         langDropdown
           .querySelectorAll("button[data-lang]")
@@ -982,6 +1004,8 @@
       const langMenu = document.getElementById("langMenu");
       const langButton = document.getElementById("langButton");
       const langDropdown = document.getElementById("langDropdown");
+      const langFlag = document.getElementById("langFlag");
+      const langLabel = document.getElementById("langLabel");
 
       /* ============================================================
        * GET ROOM FROM QUERY-PARAMETER
@@ -1501,7 +1525,19 @@ END:VCALENDAR`;
         const room = getRoom();
 
         /*
-         * Kein room-Parameter
+         * Kein room-Parameter: Meldungen ausblenden,
+         * nur den Create-Button anzeigen.
+         */
+        if (room === null) {
+          invalidRoom.querySelector("h1").classList.add("hidden");
+          invalidRoom.querySelector(".error").classList.add("hidden");
+          invalidRoom.classList.remove("hidden");
+          createNewMeetingButton.classList.remove("hidden");
+          return;
+        }
+
+        /*
+         * Ungültiger room-Parameter.
          */
         if (!isValidRoom(room)) {
           invalidRoom.classList.remove("hidden");