Siegerus's questions

window.addEventListener("DOMContentLoaded", function() {

  let menu = this.document.querySelector(".header__nav"),
    wrapper = this.document.querySelector(".header__wrap"),
    menuText = this.document.querySelector(".header__text"),
    hamburger = this.document.querySelector(".header__hamburger"),
    dropdown = this.document.querySelector(".header__dropdown");


  let menuSet = function() {

    menu.addEventListener("click", function(e) {
      if (e.target == menu || e.target == menuText || e.target == hamburger || e.target == wrapper) {
        this.classList.toggle("header__nav_active");
        menuText.classList.toggle("header__text_active");
        hamburger.classList.toggle("header__hamburger_active");
        dropdown.classList.toggle("header__dropdown_active");
      }
    });

    /* document.body.addEventListener("click", (e) => {
        if (e.target !== dropdown) {
            menu.classList.remove("header__nav_active");
            menuText.classList.remove("header__text_active");
            hamburger.classList.remove("header__hamburger_active");
            dropdown.classList.remove("header__dropdown_active");
        }
    }); */
  };

  menuSet();
});

.header__text {
  margin-left: 10px;
  font-weight: 300;
  font-size: 16px;
  text-transform: uppercase;
  line-height: 20px;
  color: #fff;
}

.header__text_active {
  color: #336ABB;
}

.header__nav {
  width: 230px;
  position: relative;
  margin-top: 3px;
  margin-left: 133.5px;
  padding: 18px 20px;
  background-color: #336ABB;
  border-radius: 10px;
}

.header__nav_active {
  background-color: #fff;
  color: #336ABB;
}

.header__dropdown {
  display: none;
  position: absolute;
  top: 39px;
  left: 0;
  width: 169px;
  padding-top: 24px;
  padding-left: 22px;
  padding-bottom: 20px;
  background: #fff;
  border-radius: 0 10px 10px 10px;
  list-style-type: none;
  box-shadow: 0 4px 18px 0 rgba(0, 0, 0, 0.25);
}

.header__dropdown_active {
  display: block;
}

.header__dropdown li {
  margin-bottom: 11px;
  color: #336ABB;
  font-weight: 300;
  font-size: 14px;
}

.header__dropdown li:nth-last-child(1) {
  margin-bottom: 0;
}

.header__wrap {
  display: flex;
  align-items: center;
}

.header__hamburger {
  display: flex;
  flex-direction: column;
  width: 19px;
  height: 10px;
}

.header__hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: #fff;
}

.header__hamburger span:nth-child(2) {
  margin: 2px 0;
}

.header__hamburger_active span {
  background-color: #336ABB;
}

.header__hamburger_active span:nth-child(1) {
  transform: translateY(3px) rotate(-45deg);
  margin-bottom: -2px;
}

.header__hamburger_active span:nth-child(2) {
  display: none;
}

.header__hamburger_active span:nth-child(3) {
  transform: translateY(3px) rotate(45deg);
  margin-bottom: 6px;
}

.title {
  margin-top: 120px;
  padding-bottom: 56px;
  font-size: 87px;
  text-align: center;
}

<div class="header__menu header__menu_m-hidden">
  <nav class="header__nav">
    <div class="header__wrap">
      <div class="header__hamburger">
        <span></span>
        <span></span>
        <span></span>
      </div>
      <div class="header__text">меню</div>
    </div>
    <ul class="header__dropdown">
      <li>Каталог</li>
      <li>Аналитика</li>
    </ul>
  </nav>
</div>
<div class="title">Lorem ipsum</div>