ナビゲーションを固定にしたときにコンテンツが隠れてしまう対処法

<header>
		<ul class="g-nav">
			<li><a href="#n1">NAVI1</a></li>
			<li><a href="#n2">NAVI2</a></li>
			<li><a href="#n3">NAVI3</a></li>
			<li><a href="#n4">NAVI4</a></li>
			<li><a href="#n5">NAVI5</a></li>
		</ul>
	</header>

	<section id="mainVisual">
		<h1>NEWYORK</h1>
	</section>

	<section id="contents">
		<div class="conts bg1">
			<h2 id="n1">CATEGORY-1</h2>
			<div>STAGE1</div>
		</div>
		<div class="conts bg2">
			<h2 id="n2">CATEGORY-2</h2>
			<div>STAGE2</div>
		</div>
		<div class="conts bg3">
			<h2 id="n3">CATEGORY-3</h2>
			<div>STAGE3</div>
		</div>
		<div class="conts bg4">
			<h2 id="n4">CATEGORY-4</h2>
			<div>STAGE4</div>
		</div>
		<div class="conts bg5">
			<h2 id="n5">CATEGORY-5</h2>
			<div>STAGE5</div>
		</div>
	</section>

	<footer>
		<h6>DemoSample</h6>
	</footer>

header{
	position:fixed;
	top:0;
	width: 100%;
}
.g-nav{
	position: relative;
	display: flex;
}
.g-nav li{
	width: 25%;
	height: 60px;
	background: #111;
	box-sizing: border-box;
	border-right: 1px solid #FFF;
	text-align: center;
	display: table;
}
.g-nav li:last-child{
	border-right: none;
}
.g-nav li a{
	display: block;
	padding: 0;
	color:#FFF;
	display: table-cell;
	vertical-align: middle;
}
.g-nav li a:hover{background: #999;}
#mainVisual{
	width: 100%;
	height: 100vh;
	background: url(../images/newyork.jpg) no-repeat;
	background-size: cover;
	display: table;
	margin-top:60px;
}
h1{
	text-align: center;
	color:#FFF;
	font-size: 100px;
	font-family: "Abril Fatface", serif;
	font-weight: 400;
	font-style: normal;
	display: table-cell;
	vertical-align: middle;
}
h2{
	text-align: center;
	color:#111;
	font-size: 80px;
	font-family: "Abril Fatface", serif;
	font-weight: 400;
	font-style: normal;
}
#wrapper{
	width: 980px;
	margin: 0 auto;
	text-align: center;
}
#contents{
	height: auto;
	background:#ccc;
}
.conts{
	height: 500px;
	border-bottom: 1px solid #111;
	text-align:center;
	padding: 60px;
}
.bg1{background: #f4b3c2;}
.bg2{background: #f8e58c;}
.bg3{background: #f9c89b;}
.bg4{background: #a59aca;}
.bg5{background: #bbc8e6;}
footer{
	width: 100%;
	height: 600px;
	display: table;
}
h6{
	display: table-cell;
	vertical-align: middle;
	text-align: center;
	font-family: "Abril Fatface", serif;
	font-weight: 400;
	font-style: normal;
}

html {
	scroll-padding-top: 120px; /* 固定ヘッダーの高さに合わせて調整します */
	scroll-snap-type: y proximity; /* 垂直方向に自然なスナップをさせる */
}