- var blocks = 16;
- var title = ["The Color Chucknorris", "The Phisherman and His Wife", "The Little Browser Engine That Couldn’t", "The DOM-Tree", "Sliding Into Auto-DMs", "Copying and Pasting from Stack Overflow","WordPress Updates Breaking Stuff","Waiting for Internet Explorer to Die","Copypaste Customer Support","Catchy Clickbait Titles and Buzzwords","Spamming with Scrapebox"];
- var bookStart = 6;
- var dummyText = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.";

mixin bookTitle(t)
  - if (t >= bookStart && t < bookStart + title.length) {
    .spine=title[t - bookStart]
  - }
  
mixin divBlock(d)
  div(class="block b" + d)
    .block-inner
      .back
      .bottom
      .front
      .left
      .right
      .top

mixin labelBlock(l)
  - var bookId = l - bookStart;
  label(for="book" + (bookId + 1),class="block b" + l)
    .block-inner
      .back
      .bottom
      .front
        +bookTitle(l)
      .left
      .right(data-title=title[bookId])
        .cover
        .contents
          h1="Chapter 1"
          p=dummyText
      .top

form.container
  - for (var r = 1; r <= title.length; ++r) {
    input(type="radio",name="title",id="book" + r)
  - }
  .surface
    - for (var b = 1;b <= blocks;++b) {
      - if (b >= bookStart && b < bookStart + title.length) {
        +labelBlock(b)
      - }
      - else {
        +divBlock(b)
      - }
    - }
  input(type="reset",value="Return")

$sqSize: 16px;
$contW: 100%;
$contH: 100%;
$xSpaces: 24;
$ySpaces: 14;
$zSpaces: 19;
$xAngle: 80deg;
$zAngle: 0deg;
$books: 11;
$bookStart: 6;
$trans: 0.25s;

// font sizing
$fFontSize: $sqSize*0.75;
$rFontSize: $sqSize*1.5;
$cntntFontSize: $sqSize*0.7;

// non-book colors
$btnColor: #c22;
$shelfColor: #441e12;

/* Block placement */
// parameters: x-pos,y-pos,z-pos, width,depth,height, color, is-book
$blocks:
  // shelf
  (2,1,1, 22,14,1, $shelfColor, false),
  (1,14,1, 24,1,18, $shelfColor, false),
  (1,1,1, 1,13,18, $shelfColor, false),
  (24,1,1, 1,13,18, $shelfColor, false),
  (1,1,19, 24,14,1, $shelfColor, false),
  // books
  (2,3,2, 2,11,14, #c00000, true),
  (4,3,2, 2,11,15, #891a21, true),
  (6,3,2, 2,10,16, #bf3e22, true),
  (8,3,2, 2,10,14, #0e4326, true),
  (10,3,2, 2,11,15, #0066cc, true),
  (12,3,2, 2,11,16, #0f7b7e, true),
  (14,3,2, 2,10,15, #084e6f, true),
  (16,3,2, 2,11,16, #0b0823, true),
  (18,3,2, 2,10,14, #38103d, true),
  (20,3,2, 2,10,15, #443344, true),
  (22,3,2, 2,10,16, #666777, true);

@mixin grid($c, $s) {
  $fontS: $s/3;
  $xC: #c00;
  $yC: #080;
  background-image:
    repeating-linear-gradient(
      180deg,
      $c,
      $c 1px,
      transparent 1px,
      transparent $s
    ),
    repeating-linear-gradient(
      -90deg,
      $c,
      $c 1px,
      transparent 1px,
      transparent $s
    );
  border-bottom: 1px solid $xC;
  border-left: 1px solid $yC;
  &::before, &::after {
    display: block;
    font-size: $fontS;
    position: absolute;
    text-align: center;
    width: $fontS;
    height: $fontS;
  }
  &::before {
    color: $yC;
    content: "y";
    top: 0;
    left: -$fontS;
  }
  &::after {
    color: $xC;
    content: "x";
    right: 0;
    bottom: -$fontS;
  }
}
@mixin placeBlock($x, $y, $z, $w, $d, $h, $c, $isBook) {
  display: block;
  transform: translate3d(
    $sqSize*($x - 1),
    $sqSize*(-$y - ($d - 1)),
    ($sqSize*$z) + ($sqSize*($h - 1))
  );
  .block-inner > div {
    background-color: $c;
	&.top, &.bottom {
      width: $sqSize * $w;
      height: $sqSize * $d;
    }
    &.top  {
      transform: rotateX(-90deg) translateY(-$sqSize*($d - 1));
    }
    &.bottom {
      transform: rotateX(-90deg) translateY(-$sqSize*($d - 1)) translateZ($sqSize*$h);
    }
	&.front, &.back, &.left, &.right {
		&::before {
			background-color: #000;
			content: "";
			width: 100%;
			height: 100%;
		}
	}
    &.front, &.back {
      width: $sqSize * $w;
      height: $sqSize * $h;
	  &::before {
	  	opacity: 0.2;
	  }
    }
    &.front {
      transform: translateZ($sqSize * ($d - 1));
    }
    &.left, &.right {
      width: $sqSize * $d;
      height: $sqSize * $h;
	  @if ($isBook == true) {
	    &::before {
	  	  opacity: 0;
	    }
	  }
	  @else {
	    &::before {
	  	  opacity: 0.4;
	    }	
	  }
    }
    &.right {
      transform: rotateY(-270deg) translate3d($sqSize, 0, $sqSize*($w - $d));
	  transform-style: preserve-3d;
	  @if ($isBook == true) {
		background-color: #fff;
		&::after {
		  background-color: $c;
		  content: attr(data-title);
		}
	  }
    }
    @if ($isBook == true) {
      $pgC: #aaa;
	  &.top, &.back, &.bottom, {
		background: {
		  	color: #fff;
			image: repeating-linear-gradient(90deg,transparent, transparent 21%, $pgC 21%, $pgC 25%, transparent 25%, transparent 46%, $pgC 46%, $pgC 50%, transparent 50%);
			size: $sqSize $sqSize;
		};
	  }
    }
  }
}
:root {
	font-size: 20px;
}
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body, input {
  font-family: "Hind", sans-serif;
  font-size: 1em;
}
body {
  background-color: #ccc;
  height: 100vh;
  margin: 0;
}
input {
	position: absolute;
}
input[type=radio] {
	top: -20px;
	left: -20px;
	&:checked ~ input[type=reset] {
		visibility: visible;
	}
}
input[type=reset] {
	background-color: $btnColor;
	border: 0;
	border-radius: 0;
	color: #fff;
	padding: 0.5em 0.75em;
	bottom: 5%;
	left: 50%;
	visibility: hidden;
	transform: translateX(-50%);
	transition: background-color 0.2s;
	-webkit-appearance: none;
	appearance: none;
	&:hover, &:focus {
		background-color: lighten($btnColor,0.2);
	}
	&:active {
		background-color: darken($btnColor,0.2);
	}
}
.container {
  animation: fadeIn $trans $trans linear forwards;
  display: flex;
  margin: auto;
  opacity: 0;
  overflow: hidden;
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  width: $contW;
  height: $contH;
  perspective: 800px;
  transform-style: preserve-3d;
}
.surface {
  //@include grid(#888, $sqSize);
  display: block;
  width: $sqSize * $xSpaces;
  height: $sqSize * $ySpaces;
  margin: auto;
  transform-style: preserve-3d;
  transform: translateY($sqSize * $zSpaces/2) rotateX($xAngle) rotateZ($zAngle);
  transition: transform $trans;
  will-change: transform;
}
.block {
  display: none;
  transform-style: preserve-3d;
  position: absolute;
  bottom: 0;
}
.block-inner div {
  display: flex;
  flex-wrap: wrap;
  align-content: flex-start;
  position: absolute;
  width: $sqSize;
  height: $sqSize;
}
.block-inner {
  position: relative;
  width: $sqSize;
  transition: transform $trans linear;
  transform-style: preserve-3d;
  transform: rotateX(-90deg) translateZ($sqSize);
}
.back {
  transform: translateZ(-$sqSize) rotateY(180deg);
}
.left {
  transform-origin: center left;
  transform: rotateY(270deg) translateX(-$sqSize);
}
.right {
  transform-origin: top right;
  &::after, div {
	top: 0;
	left: 0;
	transform-origin: 0 50%;
	transition: transform $trans $trans linear;
  }
  &::after {
  	backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    color: #fff;
  	font-size: $rFontSize;
  	line-height: $rFontSize;
	text-align: center;
	padding: 20% 5%;
	position: absolute;
	width: 100%;
	height: 100%;
	z-index: 2;
  }
  div {
    width: 100%;
    height: 100%;
  }
}
.top, .bottom {
  transform-origin: top center;
}
.spine, .right::after, .contents h1 {
  font: {
  	family: "Lora", serif;
  	weight: bold;
  };
  -webkit-font-smoothing: antialiased;
}
.spine {
  background: transparent;
  color: #ccc;
  font-size: $fFontSize;
  line-height: $fFontSize;
  top: 0;
  left: 0;
  transform: rotate(90deg) translate($sqSize*0.75,-50%);
  white-space: nowrap;
  width: 0;
  height: $sqSize;
}
.cover {
	background-color: #fff;
	z-index: 1;
}
.contents {
	font-size: $cntntFontSize;
	padding: $sqSize;
	h1 {
		font-size: 2em;
	}
	p {
		font-family: "Source Sans Pro", serif;
	}
}

// * Render blocks *
// one block only
@if length(nth($blocks,1)) == 1 {
  .b1 {
      @include placeBlock(
        nth($blocks, 1),
        nth($blocks, 2),
        nth($blocks, 3),
        nth($blocks, 4),
        nth($blocks, 5),
        nth($blocks, 6),
        nth($blocks, 7),
        nth($blocks, 8)
      );
    }
}
// more than one block
@else {
  @for $b from 1 through length($blocks) {
    .b#{$b} {
      @include placeBlock(
        nth(nth($blocks, $b), 1),
        nth(nth($blocks, $b), 2),
        nth(nth($blocks, $b), 3),
        nth(nth($blocks, $b), 4),
        nth(nth($blocks, $b), 5),
        nth(nth($blocks, $b), 6),
        nth(nth($blocks, $b), 7),
        nth(nth($blocks, $b), 8)
      );
    }
  }
}

/* Book Viewing */
label:nth-child(n+#{$bookStart}):nth-child(-n+#{$bookStart + $books}):hover .block-inner {
	transform: rotateX(-90deg) translateZ($sqSize*4);
}
@for $i from 1 through $books {
	input[type=radio]:nth-child(#{$i}) ~ .surface {
		label:nth-child(#{$i + $bookStart - 1}) .block-inner {
			animation: returnBook $trans linear;
		}
	}
	input[type=radio]:nth-child(#{$i}):checked ~ .surface {
		transform: translate(50% - (0% + ((2/$xSpaces) * 100) * $i),$sqSize * $zSpaces/2) rotateX($xAngle) rotateZ($zAngle);
		label:nth-child(#{$i + $bookStart - 1}) .block-inner {
			animation: viewBook $trans $trans linear forwards;
			&:hover {
				.right::after, .cover {
					transform: rotateY(-135deg);
				}
			}
		}
	}
}

@keyframes fadeIn {
	from {opacity: 0;}
	to {opacity: 1;}
}
@keyframes viewBook {
	from {transform: rotateX(-90deg) translateZ($sqSize*4) rotateY(0);}
	50% {transform: rotateX(-90deg) translateZ($sqSize*15) rotateY(0);}
	to {transform: rotateX(-90deg) translateZ($sqSize*15) rotateY(-90deg) rotateZ(-90deg + $xAngle) translateZ($sqSize*-5);}
}
@keyframes returnBook {
	from {transform: rotateX(-90deg) translateZ($sqSize*15) rotateY(-90deg) rotateZ(-90deg + $xAngle) translateZ($sqSize*-5);}
	50% {transform: rotateX(-90deg) translateZ($sqSize*15) rotateY(0);}
	to {transform: rotateX(-90deg) translateZ($sqSize) rotateY(0);}
}