main(role="main")
	button#popup-trigger.popup-trigger.btn: span Signup Now
			i.fa.fa-plus-square-o
#overlay.overlay
	#overlay-background.overlay-background
	#overlay-content.overlay-content
		#overlay-close.fa.fa-times.fa-lg.overlay-close
		h1.main-heading Signup Now
		h3.blurb Creating an account is free —
		span.blurb-tagline and won't take longer than a couple of seconds.
		form.signup-form(method="post",action="#",novalidate)
			label(for="signup-name") Full Name
			input#signup-name(type="text",name="name",autocomplete="off")
			label(for="signup-email") Email Address
			input#signup-email(type="email",name="email",autocomplete="off")
			label(for="signup-pw") Password
			input#signup-pw(type="password",name="pw",autocomplete="off")
			label(for="signup-cpw") Confirm Password
			input#signup-cpw(type="password",name="cpw",autocomplete="off")
			button.btn.btn-outline.submit-btn: span signup
View Compiled
// reset
* {
	margin: 0;
	padding: 0;
	color: inherit;
	box-sizing: inherit;

	&:focus {
		outline: none;
	}
}

html {
	box-sizing: border-box;
}

body {
	background-color: #ecf0f1;
	font-family: 'Open Sans', sans-serif;
	overflow: hidden;
}

h1, h2, h3, h4, h5 {
	font-weight: normal;
}

form {
	display: block;
}

label,
input {
	display: block;
}

// extends
.animate {
	transition: all 0.3s;
}

// main styles
main {
	display: block;
	width: 100%;
	height: 100%;
	position: absolute;
	top: 0;
	left: 0;
	z-index: 10;
}

.main-heading {
	line-height: 100%;
	font-weight: 600;
	font-size: 28px;
	text-transform: uppercase;
}

.btn {
	display: block;
	height: 50px;
	line-height: 50px;
	border: 0;
	text-align: center;
	cursor: pointer;
	border-radius: 5px;
	@extend .animate;

	span {
		font-weight: 600;
		font-size: 14px;
		text-transform: uppercase;
		@extend .animate;

		.fa {
			margin-left: 8px;
			font-size: 18px;
			vertical-align: middle;
		}
	}

	&:not(.btn-outline) {
		background-color: #fff;
		
		span {
			color: #666;
		}
		
		&:hover {
			background-color: #f7f7f7;
		}
	}
	
	&.btn-outline {
		background-color: transparent;
		border: 1px solid #fff;
		
		span {
			color: #fff;
		}
		
		&:hover {
			background-color: #fff;
			
			span {
				color: #666;
			}
		}
	}
}

.popup-trigger {
	width: 175px;
	margin: auto;
	position: absolute;
	top: 0;
	bottom: 0;
	left: 0;
	right: 0;
	box-shadow: 0 0 25px 0 rgba(0,0,0,.05);
}

.overlay {
	width: 100%;
	height: 100%;
	overflow: auto;
	float: left;
	position: fixed;
	top: 0;
	left: 0;
	z-index: 5;
	opacity: 0;
	transform: translateY(200px);
	transition: opacity 0.5s, transform 0.5s, z-index 0s 0.5s;
	
	.overlay-background {
		background-color: rgba(44,62,80,.8);
		width: 100%;
		height: 100%;
		position: absolute;
		top: 0;
		left: 0;
		z-index: 5;
	}
	
	.overlay-content {
		width: 100%;
		max-width: 530px;
		margin: 100px auto 0;
		padding: 0 15px;
		color: #fff;
		position: relative;
		z-index: 10;
		@extend .animate;
		
		.overlay-close {
			display: block;
			font-size: 35px;
			cursor: pointer;
			position: absolute;
			top: 0;
			right: 15px;
			@extend .animate;
			
			&:hover {
				opacity: .8;
			}
		}
		
		.blurb {
			margin-top: 35px;
			line-height: 100%;
			font-weight: 600;
			font-size: 18px;
		}
		
		.blurb-tagline {
			display: block;
			margin-top: 10px;
			line-height: 100%;
			font-size: 14px;
		}
		
		.signup-form {
			margin-top: 35px;
			
			label {
				line-height: 100%;
				margin-bottom: 5px;
				font-size: 14px;
			}
			
			input {
				background-color: transparent;
				width: 100%;
				height: 30px;
				margin-bottom: 20px;
				padding: 0 8px;
				border: 1px solid rgba(254,254,254,.3);
				border-radius: 5px;
				@extend .animate;
				
				&:hover,
				&:focus {
					border-color: #fff;
				}
			}
			
			.submit-btn {
				width: 150px;
			}
		}
	}
	
	&.open {
		z-index: 15;
		opacity: 1;
		transform: translateY(0);
		transition: opacity 0.5s, transform 0.5s, z-index 0s;
	}
	
	&.short .overlay-content {
		margin: 30px auto;
	}
}

@media (max-width: 600px) {
	
	.overlay .overlay-content {
		margin: 25px auto;
	}
}
View Compiled
calculateHeight = ->
	
	$content = $('#overlay-content')
	contentHeight = parseInt($content.height()) + parseInt($content.css('margin-top')) + parseInt($content.css('margin-bottom'))
	windowHeight = $(window).height()
	
	finalHeight = if windowHeight > contentHeight then windowHeight else contentHeight
	
	return finalHeight

$(document).ready ->
	
	$(window).resize ->
		
		if $(window).height() < 560 and $(window).width() > 600
			$('#overlay').addClass 'short'
		else
			$('#overlay').removeClass 'short'
		
		$('#overlay-background').height calculateHeight()
	
	$(window).trigger 'resize'
	
	# open
	$('#popup-trigger').click ->
		$('#overlay')
			.addClass 'open'
			.find('.signup-form input:first').select()
	
	# close
	$('#overlay-background,#overlay-close').click ->
		$('#overlay').removeClass 'open'
View Compiled
Run Pen

External CSS

  1. https://maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css
  2. https://fonts.googleapis.com/css?family=Open+Sans:400,600

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js