const NAV_SUB_CLASS = "nav-sub";
const subNav = document.querySelectorAll("." + NAV_SUB_CLASS);
const nav = document.querySelector(".nav");
const menu = document.querySelector(".menu");

subNav.forEach(node => node.addEventListener("click", (e) => {
  if (e.target !== node) return;

  if (e.target.className.match("show")) {
    e.target.className = NAV_SUB_CLASS;
  } else {
    e.target.className = NAV_SUB_CLASS + " show";
  }
}));

menu.addEventListener("click", (e) => {
  if (menu.className.match("active")) {
    menu.className = "menu";
    nav.className = "nav";
  } else {
    menu.className = "menu active";
    nav.className = "nav active";
  }
});