Header resize on scroll

index.css

header.smaller {
	height: 75px;
}

header.smaller h1#logo {
	width: 150px;
	height: 75px;
	line-height: 55px;
	font-size: 55px;
	margin: 0;
}

header.smaller nav a {
	line-height: 75px;
}

*,
*:before,
*:after {
	-webkit-box-sizing: border-box;
	-moz-box-sizing: border-box;
	box-sizing: border-box;
}

body {
	color: #505050;
	font-family: "Open Sans", sans-serif;
	font-weight: 300;
	font-size: 16px;
	line-height: 1.8;
}

h1, h2, h3, h4, h5, h6 {
	line-height: 1;
	font-weight: 100;
	color: #77C7AC;
}

a {
	text-decoration: none;
	color: #fcfcfc;
	font-weight: 300;
}

a:hover {
	color: #3c3c3c;
}

#wrapper {
	width: 100%;
	margin: 0 auto;
}

#main {
	background-color: #fff;
	padding-top: 150px;
  min-height:500px;
}

.container {
	width: 80%;
	margin: 0 auto;
	padding: 0 30px;
}

section {
	padding: 60px 0;
}

section h1 {
	font-weight: 700;
	margin-bottom: 10px;
}

section p {
	margin-bottom: 30px;
}

section p:last-child {
	margin-bottom: 0;
}

section.color {
	background-color: #f4f4f4;
}

header {
	width: 100%;
	height: 10em;
	overflow: hidden;
	position: fixed;
	top: 0;
	left: 0;
	z-index: 999;
  border-bottom:solid 0.5em #f4f4f4;
	background-color: #394e63;
	transition: height 0.3s;
}

header h1#logo {
	display: inline-block;
	line-height:3em;
   margin: 0;
   padding:0 1em;
   background-color:#fd5559;
	float: left;
	font-family: "Open Sans", sans-serif;
	font-size: 60px;
	color: #fcfcfc;
  text-shadow: 0.1em 0.03em #C0392B;
	font-weight: 400;
	-webkit-transition: all 0.3s;
	-moz-transition: all 0.3s;
	-ms-transition: all 0.3s;
	-o-transition: all 0.3s;
	transition: all 0.3s;
}

header nav {
	display: inline-block;
	float: right;
}

header nav a {
	line-height: 150px;
	margin-left: 20px;
	color: #fcfcfc;
	font-weight: 300;
	font-size: 1em;
	-webkit-transition: all 0.3s;
	-moz-transition: all 0.3s;
	-ms-transition: all 0.3s;
	-o-transition: all 0.3s;
	transition: all 0.3s;
}

header nav a:hover {
	color: #fd5559;
}

header.smaller {
	height: 75px;
}

header.smaller h1#logo {
	line-height: 75px;
	font-size: 30px;
}

header.smaller nav a {
	line-height: 75px;
}

.clearfix:after {
	visibility: hidden;
	display: block;
	content: "";
	clear: both;
	height: 0;
}

@media all and (max-width: 760px) {
	header h1#logo {
		display: block;
		float: none;
		margin: 0 auto;
		height: 100px;     
		line-height: 80px;
		text-align: center;
	}

	header nav {
		display: block;
		float: none;
		height: 50px;
		text-align: center;
		margin: 0 auto;
	}

	header nav a {
		line-height: 50px;
		margin: 0 10px;
	}

	header.smaller {
		height: 75px;
	}

	header.smaller h1#logo {
		height: 40px;
		line-height: 40px;
		font-size: 30px;
     width:100%;
	}

	header.smaller nav {
		height: 35px;
	}

	header.smaller nav a {
		line-height: 35px;
	}

}

@media all and (max-width: 600px) {
	.container {
		width: 100%;
	}
}

index.html

<div id="wrapper">
  <header id="js-header">
      <div class="container clearfix">
          <h1 id="logo">Apples</h1>
          <nav>
              <a href="#bacon">Bacon</a>
              <a href="#sausage">Sausage</a>
              <a href="#biltong">Biltong</a>
          </nav>
      </div>
  </header>
</div>

index.js

function resizeHeaderOnScroll() {
  const distanceY = window.pageYOffset || document.documentElement.scrollTop,
  shrinkOn = 200,
  headerEl = document.getElementById('js-header');
  
  if (distanceY > shrinkOn) {
    headerEl.classList.add("smaller");
  } else {
    headerEl.classList.remove("smaller");
  }
}

window.addEventListener('scroll', resizeHeaderOnScroll);