【jQuery】全画面表示のナビゲーションメニューを実装する

<a class="toggle-btn">
    <span class="toggle-btn__line toggle-btn__line--top"></span>
    <span class="toggle-btn__line toggle-btn__line--center"></span>
    <span class="toggle-btn__line toggle-btn__line--bottom"></span>
</a>

<nav class="global-nav">
    <div class="global-nav__inner">
        <ul class="global-nav__list">
            <li class="global-nav__item"><a href="#">TOP</a></li>
            <li class="global-nav__item"><a href="#">ABOUT</a></li>
            <li class="global-nav__item"><a href="#">WORKS</a></li>
            <li class="global-nav__item"><a href="#">CONTACT</a></li>
        </ul>
    </div>
</nav>

<div class="main"></div>

/* ハンバーガーボタン
==============================　*/
.toggle-btn {
  width: 30px;
  height: 30px;
  position: absolute;
  right: 20px;
  top: 20px;
  z-index: 2;
}

.toggle-btn__line {
  background: #fff;
  display: block;
  height: 2px;
  position: absolute;
  transition: transform 0.5s;
  width: 100%;
}

.toggle-btn__line--top {
  top: 3px;
}

.toggle-btn__line--center {
  top: 15px;
}

.toggle-btn__line--bottom {
  top: 27px;
}

.toggle-btn__line--top.active {
  top: 15px;
  transform: rotate(45deg);
}
.toggle-btn__line--center.active {
  transform: scaleX(0);
}
.toggle-btn__line--bottom.active {
  top: 15px;
  transform: rotate(135deg);
}

/* ナビゲーションメニュー
==============================　*/
.global-nav {
  display: none;
  position: fixed;
  background: rgba(0, 0, 0, 0.7);
  width: 100%;
  height: 100%;
  z-index: 1;
}

.global-nav__inner {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
}

.global-nav__item {
  margin-bottom: 30px;
}

.global-nav__item a {
  color: #fff;
  font-size: 30px;
  font-weight: bold;
  text-decoration: none;
  transition: 0.5s;
}

.global-nav__item a:hover {
  opacity: 0.7;
}

/* メイン画面
==============================　*/
.main {
  background: url(http://note.spiqa.design/wordpress/wp-content/uploads/2021/04/sky-scaled.jpg)
    center center no-repeat;
  background-size: cover;
  height: 100vh;
}

jQuery(document).ready(function($){
$('.toggle-btn').on('click',function(){
    $('.toggle-btn__line').toggleClass('active');
    $('.global-nav').fadeToggle();
});
});