header - slowly moving

by sharzy

HTML

<div class="header">
  <div class="sides">
    <a href="#" class="logo">BLOG</a>
  </div>
  <div class="sides"> <a href="#" class="menu"> </a></div>
  <div class="info">
  <h4><a href="#category">UI DESIGN</a></h4>
    <h1>KEN BURNS HEADERS ARE THE BEST</h1>
    <div class="meta">
      <a  href="https://twitter.com/nodws" target="_b" class="author"></a><br>
      By <a href="https://twitter.com/nodws" target="_b">James Nodws</a> on May 30, 2019
    </div>
  </div>
</div>
<section class="content">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. In nisl turpis, porttitor et finibus id, viverra a metus. Praesent non ante sed orci posuere varius quis sit amet dui. Cras molestie magna orci, id gravida dolor molestie in. Duis sollicitudin turpis quis tortor egestas, ut ultrices nisl elementum. Vestibulum sed ipsum eget nulla laoreet cursus in ac sem. Integer a suscipit justo, quis aliquam sapien. Maecenas et tellus nibh. Vivamus tincidunt eros id commodo pellentesque.</p>
  <p align="center"><a href="https://twitter.com/nodws" class="btn twtr" target="_b">Follow me on Twitter</a>
  </p>
</section>

CSS

@import url('https://fonts.googleapis.com/css?family=Josefin+Sans:400,400i,600,600i');
html,body{
  margin:0;
  height:120%;
  font-family: 'Josefin Sans', sans-serif;

}
a{
  text-decoration:none
}
.header{
  position:relative;
  overflow:hidden;
  display:flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: flex-start;
  align-content: flex-start;
  height:50vw;
  min-height:400px;
  max-height:550px;
  min-width:300px;
  color:#eee;
}
.header:after{
  content:"";
  width:100%;
  height:100%;
  position:absolute;
  bottom:0;
  left:0;
  z-index:-1;
 background: linear-gradient(to bottom, rgba(0,0,0,0.12) 40%,rgba(27,32,48,1) 100%);
}
.header:before{
  content:"";
  width:100%;
  height:200%;
  position:absolute;
  top:0;
  left:0;
    -webkit-backface-visibility: hidden;
    -webkit-transform: translateZ(0); backface-visibility: hidden;
  scale(1.0, 1.0);
    transform: translateZ(0);
  background:#1B2030 url(https://images.unsplash.com/photo-1571993142257-eae0b44cf0f1?ixlib=rb-1.2.1&q=85&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjE0NTg5fQ) 50% 0 no-repeat;
  background-size:100%;
  background-attachment:fixed;
  animation: grow 360s  linear 10ms infinite;
  transition:all 0.4s ease-in-out;
  z-index:-2
}
.header a{
  color:#eee
}
.menu{
  display:block;
  width:40px;
  height:30px;
  border:2px solid #fff;
  border-radius:3px;
  position:absolute;
  right:20px;
  top:20px;
  text-decoration:none
}
.menu:after{
  content:"";
  display:block;
  width:20px;
  height:3px;
  background:#fff;
  position:absolute;
  margin:0 auto;
  top:5px;
  left:0;
  right:0;
  box-shadow:0 8px, 0 16px
}
.logo{
  border:2px solid #fff;
  border-radius:3px;
  text-decoration:none;
  display:inline-flex;
  align-items:center;
  align-content:center;
  margin:20px;
  padding:0px 10px;
  font-weight:900;
  font-size:1.1em;
  line-height:1;
  box-sizing:border-box;
  height:40px
}
.sides, .info{
  flex: 0 0 auto;
  width:50%
}
.info{
  width:100%;
  padding:15% 10% 0...

JavaScript

// find elements
var banner = $("#banner-message")
var button = $("button")

// handle click and add class
button.on("click", function(){
  banner.addClass("alt")
})