fix typo

js/customElements/mainMenu.js

@@ -7,14 +7,14 @@ class MainMenu extends HTMLElement {
     async generateMenu() {
         let menu = await (await fetch("/API/mainMenu.json")).json();
         let menuContainer = document.createElement("div");
-        menuContainer.className = "mainMenuContainer";
+        menuContainer.className = "mainmenuContainer";
 
         let burgerMenu = document.createElement("div");
         burgerMenu.id = "burgerMenu";
 
         burgerMenu.onclick = () => {
             document.getElementById("burgerMenu").classList.toggle("change");
-            document.querySelector(".mainMenuContainer").classList.toggle("visible");
+            document.querySelector(".mainmenuContainer").classList.toggle("visible");
 
         }