Не корректно работает бургер меню, меню не пропадает когда закрыт бургер

let nav = document.querySelector('.nav__main').cloneNode(1)
let nav2 = document.querySelector('.block_manu')
let btnMenu = document.getElementsByClassName("btn-menu");
let body = document.body
let bcgBurger = document.querySelector('.background_burger')
for (let i = 0; i < btnMenu.length; i++) {
  btnMenu[i].addEventListener('click', () => {
    body.classList.toggle('menu-open');
    bcgBurger.classList.toggle('background_burger_active');
    render()
  });
}

function render() {
  nav2.appendChild(nav)
}

.btn-menu {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 21px;
  padding-left: 0;
  padding-right: 0;
  border: none;
  background-color: transparent;
  color: inherit;
  cursor: pointer;
  transition: 0.3s ease;
}

.btn-menu:focus {
  outline: none;
}

.btn-menu__text {
  margin-left: 10px;
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1;
}

.btn-menu__bars {
  display: block;
  position: relative;
  width: 36px;
  height: 3px;
  background-color: #bebebe;
  transition: 0.3s;
}

.btn-menu__bars:before,
.btn-menu__bars:after {
  content: "";
  display: block;
  position: absolute;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #bebebe;
  transition: 0.3s;
}

.btn-menu__bars:before {
  transform: translate(0, -9px);
}

.btn-menu__bars:after {
  transform: translate(0, 9px);
}

.menu-open .btn-menu .btn-menu__bars {
  background-color: transparent;
}

.menu-open .btn-menu .btn-menu__bars:before {
  transform: rotate(45deg);
}

.menu-open .btn-menu .btn-menu__bars:after {
  transform: rotate(-45deg);
}


/* BACKGROUND */

.background_burger {
  top: 0;
  left: 0;
  z-index: 0;
  background-color: #1B1A1F;
  width: 0%;
  height: 100vh;
  position: absolute;
  transition: 1s;
}

.background_burger_active {
  top: 0;
  left: 0;
  z-index: 0;
  background-color: #1B1A1F;
  width: 100%;
  height: 100vh;
  position: absolute;
  transition: 1s;
}

<header class="header">
  <div class="header__logo border">
    <button class="btn-menu" type="button">
                <i class="btn-menu__bars" aria-hidden="true"></i>
                <span class="visually-hidden"></span>
            </button>
    <div class="background_burger">
      <div class="block_manu">
      </div>
    </div>
  </div>
</header>
<nav class="nav">
  <ul class="nav__main" id="nav__main">
    <li class="nav__list"><span class="material-symbols-outlined">equalizer</span><a href="#" class="nav__list-item">Chart</a></li>
    <li class="nav__list"><span class="material-symbols-outlined">search</span><a href="#" class="nav__list-item">Search</a></li>
  </ul>
</nav>