Expanded div

by tanaan

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<!-- container -->
  <div class="container-fluid">

    <!-- header -->   
    <header class="row">
     
    </header>
    
    <!-- content -->
    <main class="row clearfix"></main>

  </div>

CSS

body{
	height: 3000px;
	margin: 0;
}

*{
	box-sizing: border-box;
}


/* HEADER */

header {
	padding-top: 0px;
	margin-bottom: 0px;
	background-color: #ccc;
	font-size: 1em;
	overflow: hidden;
	z-index: 1000;
	height: 100px;
	position: fixed;
	width: 100%;
}


.header2{
	position: fixed;
	height: 75px;
	width: 100%;
	background-color: #ff0000;
	/*padding-top: 10px;*/
}


main {
	min-height: 100vh;
  	display: block;
  	margin: 0 auto;
    margin-top: 100px; /* Cambio esto para controlar la distancia con el top */
}
#og-grid{
	padding: 0;
	margin: 0;
}

.portfolio {
	display: flex;
	flex-wrap: wrap;
	list-style-type: none;
	position: relative;
}

.portfolio > div {
	flex-basis: calc(20% - 0rem);
	cursor: pointer;
}

.portfolio > div > .content {
  	display: none;
}
.portfolio > .animator > .content {
  	display: block;
}
.portfolio > .animator {
  	flex-basis: calc(100% - 0rem);
}

.portfolio>div {
	display: flex;
	flex-direction: column;
	align-items: center;
	justify-content: center;
	margin: 0rem;
}
.portfolio>.animator {
	background-color: #fff;
	color: #333;
	margin: 0rem;
	cursor: initial;
}

.portfolio >.animator {
	padding: 0;
	overflow: hidden;
	max-height: 0;
	transition: max-height .3s cubic-bezier(.4,0,.2,1);
	border: 0;
}
.portfolio >.animator >.content {
	padding: 3rem 0;
}

.workswrap{
	display: inline-block;
	margin: 0;
	padding: 0;
	width: 20%;
	float: left;
	vertical-align: top;
}

.workswrap .imagewrap{
	overflow: hidden;
	position: relative;
}

.workswrap.active .workhover {
	display: none;
}
.workswrap.active .workactive {
	display: block;
}
.workswrap.active .workactive .workinfo {
	display: block;
	opacity: 1;
}

/* NAVIGATION BUTTONS */

.portfolio .buttons {
  	display: flex;
    justify-content: space-around;
    margin: 1rem
}

.portfolio .buttons > * {
	padding: 3px 10px;
	border: 1px solid white;
	margin: 0 .5rem;
	cursor:pointer;
}

.btn-prev{
	position: absolute;
	left: 0;
	top: 50%;
}

.btn-next{
	position: absolute;
	right:...

JavaScript

$(window).scroll(function(){

		if( $(this).scrollTop() > 0 ){
			$('header').addClass('header2');
			$('main').css('margin-top',75);
		} else {
			$('header').removeClass('header2');
			$('main').css('margin-top',100);
		}
	      
	});

	var main = [{
		title:'Neymar Jr.',
		idProject: 'first',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t1.jpg',
		categoryProject: 'Web Design',
		tagsProject: ['tag1,', 'tag2']
	},{
		title:'Title grid 2',
		idProject: 'second',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t2.jpg',
		categoryProject: 'Branding',
		tagsProject: ['tag16,', 'tag5']
	},{
		title:'Title grid 3',
		idProject: 'third',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t1.jpg',
		categoryProject: 'Printing',
		tagsProject: ['tag3,', 'tag8']
	},{
		title:'Title grid 4',
		idProject: 'fourth',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t2.jpg',
		categoryProject: 'Illustration',
		tagsProject: ['tag5,', 'tag9']
	},{
		title:'Title grid 5',
		idProject: 'fifth',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t1.jpg',
		categoryProject: 'Web Design',
		tagsProject: ['tag2,', 'tag7']
	},{
		title:'Title grid 6',
		idProject: 'sixth',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t2.jpg',
		categoryProject: 'Logo',
		tagsProject: ['tag8,', 'tag6']
	},{
		title:'Title grid 7',
		idProject: 'seventh',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t1.jpg',
		categoryProject: 'Branding',
		tagsProject: ['tag3,', 'tag4']
	},{
		title:'Title grid 8',
		idProject: 'eighth',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t2.jpg',
		categoryProject: 'Printing',
		tagsProject: ['tag34,', 'tag98']
	},{
		title:'Title grid 9',
		idProject: 'ninth',
		content: '',
		imageProject: 'http://tanaanstudio.com/again/images/t1.jpg',
		categoryProject: 'Illustration',
		tagsProject: ['tag11,',...