<!-- Gallery -->
<main id="js-gallery" role="main" class="gallery">

	<section class="gallery__body">

		<div id="js-poster" class="main__gallery-poster poster">
			<div class="poster__content">

				<header class="poster__header">
					<h1>jazz &amp; pop schallplattenhüllen</h1>
					<ul>
						<li>funktion und bildwelten</li>
						<li>ausstellung im kunstgewerbemuseum zürich</li>
						<li>ausstellungsstrasse 60</li>
						<li>1. juli bis 13. august 1978</li>
					</ul>
					<h2>öffnungszeiten:</h2>
					<dl>
						<dt>di do fr</dt>
						<dd>10-18h</dd>
					</dl>
					<dl>
						<dt>mi</dt>
						<dd>10-21h</dd>
					</dl>
					<dl>
						<dt>sa so</dt>
						<dd>10-12h <span>14-17h</span></dd>
					</dl>
					<dl>
						<dt>mo</dt>
						<dd>geschlossen</dd>
					</dl>
					<p>organisiert durch den neuen berliner kunstverein nbk</p>
				</header>

				<section class="poster__body">
					<div></div>
				</section>

			</div>
			<!-- .poster__content -->
		</div>
		<!-- .poster -->

	</section>
	<!-- .gallery__body -->

</main>
<!-- .gallery -->
<!-- Gallery -->

/**
 * Mixins
 */
@mixin pos ($position, $top: auto, $right: auto, $bottom: auto, $left: auto) {
  position: $position;
  top: $top;
  right: $right;
  bottom: $bottom;
  left: $left;
}

@mixin center($width: null, $height: null) {
  position: absolute;
  top: 50%;
  left: 50%;
  @if not $width and not $height {
    transform: translate(-50%, -50%);
  } @else if $width and $height {
    width: $width;
    height: $height;
    margin: -($width / 2) #{0 0} -($height / 2)
  } @else if not $height {
    margin-left: -($width / 2);
    transform: translateY(-50%);
    width: $width;
  } @else {
    margin-top: -($height / 2);
    transform: translateX(-50%);
    height: $height;
  }
}


/**
 * Variables
 */

// Colors
$primary-color: #999;
$off-white: #F5F5F5;
$black: #222;
$red: #D92A00;
$blue: #0098D8;
$green: #007500;

// Animations
$duration: 10s;
$timing: cubic-bezier(0.455,  0.030, 0.515, 0.955);

// Spacing
$spacing: 20px;


/**
 * Animations
 */
@keyframes shiftBorderColor {
    0% {
        border-color: $red;
    }
    33.3333% {
        border-color: $green;
    }
    66.6666% {
        border-color: $blue;
    }
}

@keyframes shiftTextColor {
    0% {
        color: $red;
    }
    33.3333% {
        color: $green;
    }
    66.6666% {
        color: $blue;
    }
}

@keyframes shiftBackgroundColor {
    0% {
        background: $red;
    }
    33.3333% {
        background: $green;
    }
    66.6666% {
        background: $blue;
    }
}


/**
 * Base
 */
*,
*:after,
*:before {
    box-sizing: border-box;
}

body {
  font-family: "Helvetica Neue","Helvetica", sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: bold;
}


/**
 * Gallery
 */
.gallery {
  @include pos(absolute, 0, 0, 0, 0);
  z-index: 1;
  width: 100%;
  height: 100%;
  overflow: hidden;
}

.gallery__body {
  @include center();
  transform-origin: center center;
}


/**
 * Poster
 */
.poster {
  @include center();
  transform-origin: center center;
  display: inline-block;
  vertical-align: middle;

  &:before,
  &:after {
    z-index: -1;
    position: absolute;
    content: "";
    bottom: 15px;
    left: 8px;
    width: 50%;
    top: 80%;
    max-width: 300px;
    background: #777;
    box-shadow: 0 15px 10px rgba(#000,.5);
    transform: rotate(-3deg);
  }

  &:after {
    transform: rotate(3deg);
    right: 8px;
    left: auto;
  }
}

.poster__content {
  position: relative;
  width: 500px;
  height: 700px;
  overflow: hidden;
	padding: 2%;
  background-color: $primary-color;
  color: white;
  box-shadow: 0 1px 4px 2px rgba(#000,.2);
}

.gallery {
    background-color: $red;
    animation: shiftBackgroundColor $duration $timing infinite;
}

.poster__content {
    padding: $spacing;
    background-color: $off-white;
    color: black;
}

.poster__header {
    h1,
    h2,
    li,
    dl,
    p {
        font-size: 15px;
        font-weight: bold;
        line-height: 1;
        border-top: 1px solid $black;
    }

    h1 {
        color: $red;
        animation: shiftTextColor $duration $timing infinite;
    }

    dt {
        width: 15%;
    }

    dt,
    dd {
        display: inline-block;
    }

    span {
        display: inline-block;
        margin-left: 10px;
    }

    p {
        border-bottom: 1px solid $black;
    }
}

.poster__body {
    position: absolute;
    right: $spacing;
    bottom: $spacing;
    left: $spacing;
    height: 66%;
    padding: $spacing/2;
    border: 12px solid $red;
    animation: shiftBorderColor $duration $timing infinite;

    div {
        width: 100%;
        height: 100%;
        background-color: $black;
        border-radius: 50%;

        &:before {
            content: "";
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            display: block;
            width: 30%;
            height: 30%;
            border: 60px solid $off-white;
            border-radius: 50%;
        }
    }
}

(function(window, document, undefined) {

    'use strict';


    /**
     * Selectors
     */
    var body = document.body,
        gallery = document.getElementById('js-gallery'),
        galleryWidth = gallery.offsetWidth,
        galleryHeight = gallery.offsetHeight,
        poster = document.getElementById('js-poster'),
        posterWidth = poster.offsetWidth,
        posterHeight = poster.offsetHeight,
        posterPadding = '50';


    /**
     * Prefixed requestAnimationFrame
     */
    var requestAnimationFrame = window.requestAnimationFrame
    || window.webkitRequestAnimationFrame
    || window.mozRequestAnimationFrame
    || window.msRequestAnimationFrame
    || function(callback) {
        return setTimeout(callback, 1000 / 60);
    };


    /**
     * Methods
     */
    var throttle = function(callback, limit) {
        var wait = false;
        return function() {
            if (!wait) {
                callback.call();
                wait = true;
                setTimeout(function() {
                    wait = false;
                }, limit);
            }
        };
    };

    var resizePoster = function() {

        // Define variable
        var scale;

        // Get values for poster dimensions
        scale = Math.min(
            galleryWidth / posterWidth,
            galleryHeight / posterHeight
        );


				// Scale Poster for larger viewports
				poster.style[Modernizr.prefixed('transform')] = 'translate(-50%, -50%) ' + 'scale(' + scale + ')';

        // Sync operation with browser
        requestAnimationFrame(resizePoster);
    };


    var onResize = throttle(function() {

        // Set Gallery width
        galleryWidth = gallery.offsetWidth - posterPadding;

        // Set Gallery height
        galleryHeight = gallery.offsetHeight - posterPadding;

        // Sync operation with browser
        requestAnimationFrame(resizePoster);

    }, 100);


    /**
     * Events/APIs/init
     */

    // Set Gallery width
    galleryWidth = gallery.offsetWidth - posterPadding;

    // Set Gallery height
    galleryHeight = gallery.offsetHeight - posterPadding;

    // Sync operation with browser
    requestAnimationFrame(resizePoster);

    // Listen for resize event
    window.addEventListener('resize', onResize, false);

})(window, document);