ドロップダウンメニューの作成 - WEBサイト制作の勉強

<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>ドロップダウンメニューの作成</title>
<link rel="stylesheet" href="css/style.css">
</head>
<body>
<header>
<h1>ロゴ</h1>
<nav id="g-nav">
<ul>
<li><a href="#">MEN</a></li>

<li><a href="women/index.html">WOMEN</a>
<div class="drop-menu">
<div class="drop-box">
<a href="women/index.html#shoes">
<p class="drop-photo"><img src="img/nav-01.jpg" alt=""></p>
<p>シューズ</p>
</a>
</div><!-- /.drop-box -->
<div class="drop-box">
<a href="women/index.html#wear">
<p class="drop-photo"><img src="img/nav-02.jpg" alt=""></p>
<p>ウェア</p>
</a>
</div><!-- /.drop-box -->
<div class="drop-box">
<a href="women/index.html#sports">
<p class="drop-photo"><img src="img/nav-03.jpg" alt=""></p>
<p>スポーツ</p>
</a>
</div><!-- /.drop-box -->
<div class="drop-box">
<a href="women/index.html#brand">
<p class="drop-photo"><img src="img/nav-04.jpg" alt=""></p>
<p>ブランド</p>
</a>
</div><!-- /.drop-box -->
</div><!-- /.drop-menu -->
</li>
<li><a href="#">KIDS</a></li>
<li><a href="#">CUSTOMIZE</a></li>
<li><a href="#">SALE</a></li>
</ul>
</nav>
<div class="sns">
<p><img src="img/instagram-brands.svg" alt=""></p>
<p><img src="img/envelope-regular.svg" alt=""></p>
</div>
</header>
</body>
</html>

style.css

@charset "utf-8";

header{
height: 80px;
background-color: #e6f5fb;
display: flex;
align-items: center;
justify-content: space-between;
padding: 0 20px;
position: relative;
}
h1{
width: 10%;
text-align: center;
}
#g-nav>ul{
display: flex;
}
#g-nav li{
margin: 0 20px;
}
#g-nav>ul>li>a{
display: block;
color: #222;
line-height: 80px;
padding: 0 10px;
font-weight: bold;
}
#g-nav>ul>li>a:hover{
text-decoration: underline 3px;
text-underline-offset: 3px;
}
.drop-menu{
position: absolute;
left: 0;
top: 80px;
width: 100%;
height: 400px;
background-color: #d1d1d1;
display: flex;
justify-content: center;
padding-top: 80px;
opacity: 0;
visibility: hidden;
}
#g-nav li:hover>.drop-menu{
opacity: 1;
visibility: visible;
transition: 0.5s;
}
.drop-box{
width: 18%;
margin: 0 16px;
}
.drop-box>a{
color: #222;
margin-top: 12px;
font-size: 20px;
}
.drop-photo{
overflow: hidden;
margin-bottom: 6px;
}
.drop-box img{
transition: 0.3s;
}
.drop-box>a:hover img{
transform: scale(1.1);
}
.sns{
display: flex;
width: 10%;
justify-content: space-between;
}
.sns>p{
width: 44px;
}