I would like to make animated show and hide navigation menu like in [this webiste](http://be.beantownthemes.com/html/index-barman.html)

I tried to do it with JS

```
const body = document.getElementsByTagName("body")[0];
let element = document.querySelector(".navigation");
let button = document.querySelector(".menu-button");

 button.addEventListener("click", function() {
  button.classList.toggle("menu-button--changed");
  element.classList.toggle("navigation--show");
});

```

And width scss

```
.navigation {
  background-color: rgb(14, 14, 23);
  width: 250px;
  height: 100vh;
  position: fixed;
  right: 0;
  top: 0;
  z-index: 3;
  padding: 6rem 0 2rem 0rem;
  transition: transform 0.3s ease-out;
  transform: translateX(30rem);
  &--show {
    transform: translateX(0rem);
  }

 &__item {
    list-style: none;
    border-top: 1px solid rgba(255, 255, 255, 0.03);

    &:last-child {
      border-bottom: 1px solid rgba(255, 255, 255, 0.03);
    }
  }
  &__link {
    color: #fff;
    text-decoration: none;
    display: block;
    padding: 11px 5px 10px 20px;
    font-size: 1.4rem;

    &:hover {
      text-transform: uppercase;
    }
  }
}

```

HTML 

```
<!-- Mobile menu button -->
  <div class="menu-button">
    <div class="menu-button--bar"></div>
  </div>

  <!-- Navigation -->
  <div class="navigation">
    <nav class="menu__nav">
      <ul class="navigation__list">
        <li class="navigation__item"><a class="navigation__link" href="#">Home</a></li>
        <li class="navigation__item"><a class="navigation__link" href="#">Contact</a></li>
        <li class="navigation__item"><a class="navigation__link" href="#">Group</a></li>
      </ul>
    </nav>
  </div>

  <div class="content-wrapper">
    <!-- Header -->
    <div class="main-header">
      <img src="img/logo-retina-1.png" class="main-header__logo">
      <div class="main-header__bg"></div>
      <div class="main-header__bg--decoder"></div>
    </div>

```

But it doesn't work correctly. I don't know how to move body to left, when I show menu, and change it to more darkly. 
I tried to add, but animation doesn't work.