.container
  %h1 Menu Button to Hamburger
  %p.sub-title Styled & Animated With Pure CSS
  %button{} Menu
  %div.buttons
    %ol
      - 20.times do
        %li
          %button{:class => 'menu-toggle'} Menu

@mixin flexbox {
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  display: -webkit-flex;
  display: flex;
}

@mixin flex-vertical {
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -webkit-flex-flow: column wrap;
  -ms-flex-flow: column wrap;
  flex-flow: column wrap;
  -webkit-justify-content: center;
  justify-content: center;
}

@mixin flex-horizontal {
  -webkit-box-orient: horizontal;
  -webkit-box-direction: normal;
  -webkit-flex-flow: row wrap;
  -ms-flex-flow: row wrap;
  flex-flow: row wrap;
  -webkit-justify-content: flex-start;
  justify-content: flex-start;
}

@mixin bgcolors($max-count) {
  $color: 360/$max-count;
  
  @for $i from 1 through $max-count {
    &:nth-child(#{$max-count}n + #{$i}):hover {
      
      $hue: ($i - 1)*$color;
      
      background: hsl($hue, 80%, 55%);
      
      @if $hue < 185 and $hue > 45 {
        color: #222;
      }
      @else {
        color: #FFF;
      }
    }
  }
}

.buttons * {
  padding: 0;
}

body {
  font: 100% Helvetica, sans-serif;
  color: #333;
  padding: 0;
  margin: 0;
  background: #F7F7F7;
  text-align: center;
}

h1,
p.sub-title {
  text-transform: uppercase;
  letter-spacing: 0.2em;
}

h1,
.buttons {
  margin-top: 50px;
}

.buttons {
  ol {
    padding: 0;
    margin-left: 2.5vw;
    list-style: none;
    @include flexbox;
    @include flex-horizontal;
    
    li {
      position: relative;
      width: 23vw;
      height: 23vw;
      cursor: pointer;
      margin: 0 1vw 3vw 0;
      background: #FFF;
      transition: background 0.35s;
      counter-increment: list-counter;
      
      @include flexbox;
      @include flex-vertical;
      @include bgcolors(20);
      
      &:nth-child(4n) {
        margin-right: 0;
      }
      
      @media screen and (max-width : 768px) {
        & {
          width: 46vw;
          height: 46vw;
          margin: 0 4vw 4vw 0;
        }
        
        &:nth-child(2n) {
          margin-right: 0;
        }
      }
      
      &:before {
        position: absolute;
        bottom: 0;
        left: 0;
        z-index: -1;
        display: block;
        width: 23vw;
        height: 20vw;
        content: "";
        box-shadow: 0 0 20px rgba(0, 0, 0, 0.05);
      }
      
      &:after {
        position: absolute;
        top: 38%;
        right: 7vw;
        transform: rotate(-90deg);
        z-index: 1;
        display: block;
        width: 30px;
        height: 30px;
        text-align: center;
        content: counter(list-counter, decimal-leading-zero);
        font-family: Helvetica;
        font-size: 20px;
        line-height: 30px;
        font-weight: 300;
        opacity: 0.15;
        transition: color 0.35s;
        will-change: color;
      }
      
      button {
        position: relative;
        display: block;
        width: 50px;
        height: 1px;
        margin: 0 auto;
        border: none;
        cursor: pointer;
        background: currentColor;
        color: inherit;
        font-size: 0;
        transition: 0.35s;
        
        &:before,
        &:after {
          position: absolute;
          top: 0;
          left: 50%;
          display: block;
          width: 100%;
          height: 1px;
          background: currentColor;
          content: "";
          transition: transform 0.35s;
        }
        
        &:before {
          transform: translate(-50%, -14px);
        }
        
        &:after {
          transform: translate(-50%, 14px);
        }
      }
      
      &:nth-child(1) {
        button {
          &:before,
          &:after {
            transform-origin: 0% 0%;
          }
        }
        
        &:hover button {
          &:before {
            transform: translate(-50%, 0) rotate(-35deg) scaleX(0.6);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(35deg) scaleX(0.6);
          }
        }
      }
      
      &:nth-child(2) {
        button {
          &:before,
          &:after {
            transform-origin: 50% 0%;
          }
        }
      
        &:hover button {
          background: transparent;
          
          &:before {
            transform: translate(-50%, 0) rotate(45deg);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(-45deg);
          }
        }
      }
      
      &:nth-child(3) {
        button {
          &:before,
          &:after {
            transform-origin: 100% 0%;
          }
        }
      
        &:hover button {
          &:before {
            transform: translate(-50%, 0) rotate(35deg) scaleX(0.6);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(-35deg) scaleX(0.6);
          }
        }
      }
      
      &:nth-child(4) {
        button {
          &:before,
          &:after {
            transform-origin: 0% 0%;
          }
        }
      
        &:hover button {
          transform: rotate(-90deg);
          
          &:before {
            transform: translate(-50%, 0) rotate(-45deg) scaleX(0.8);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(45deg) scaleX(0.8);
          }
        }
      }
      
      &:nth-child(5) {
        button {
          &:before,
          &:after {
            transform-origin: 0% 0%;
          }
        }
      
        &:hover button {
          transform: rotate(90deg);
          
          &:before {
            transform: translate(-50%, 0) rotate(-45deg) scaleX(0.8);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(45deg) scaleX(0.8);
          }
        }
      }
      
      &:nth-child(6) {
        button {
          &:before,
          &:after {
            transform-origin: 0% 0%;
          }
        }
      
        &:hover button {
          background: transparent;
          
          &:before {
            transform: translate(-50%, 0) rotate(-45deg) scaleX(0.7);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(45deg) scaleX(0.7);
          }
        }
      }
      
      &:nth-child(7) {
        button {
          &:before,
          &:after {
            transform-origin: 100% 0%;
          }
        }
      
        &:hover button {
          background: transparent;
          
          &:before {
            transform: translate(-50%, 0) rotate(45deg) scaleX(0.7);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(-45deg) scaleX(0.7);
          }
        }
      }
      
      &:nth-child(8) {
        button {
          &:before,
          &:after {
            transform-origin: 100% 0%;
          }
        }
      
        &:hover button {
          transform: rotate(90deg);
          background: transparent;
          
          &:before {
            transform: translate(-50%, 0) rotate(45deg) scaleX(0.7);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(-45deg) scaleX(0.7);
          }
        }
      }
      
      &:nth-child(9) {
        button {
          transition: 0s;
          
          &:before,
          &:after {
            transform-origin: 50% 0%;
          }
        }
      
        &:hover button {
          background: transparent;
          
          &:before {
            animation: menuBefore 0.5s forwards;
          }
          
          &:after {
            animation: menuAfter 0.5s forwards;
          }
        }
      }
      
      @keyframes menuBefore {
        0% {
          transform: translate(-50%, -14px);
        }
        40% {
          transform: translate(-50%, 0);
        }
        60% {
          transform: translate(-50%, 0);
        }
        100% {
          transform: translate(-50%, 0) rotate(45deg);
        }
      }
      @keyframes menuAfter {
        0% {
          transform: translate(-50%, 14px);
        }
        40% {
          transform: translate(-50%, 0);
        }
        60% {
          transform: translate(-50%, 0);
        }
        100% {
          transform: translate(-50%, 0) rotate(-45deg);
        }
      }
      
      &:nth-child(10) {
        button {
          transition: transform 0.35s 0s;
          
          &:before,
          &:after {
            transform-origin: 0% 0%;
            transition: transform 0.35s 0.35s;
          }
        }
      
        &:hover button {
          transform: rotate(-90deg);
          transition: transform 0.35s 0.35s, background 0.35s 0s;
          
          &:before {
            transform: translate(-50%, 0) rotate(-45deg) scaleX(0.8);
            transition: transform 0.35s 0s;
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(45deg) scaleX(0.8);
            transition: transform 0.35s 0s;
          }
        }
      }
      
      &:nth-child(11) {
        button {
          transition: 0.1s;
          
          &:before,
          &:after {
            transform-origin: 100% 0%;
          }
          
          &:after {
            transition-delay: 0.15s;
          }
        }
      
        &:hover button {
          transform: translateX(8px);
          transition: transform 0.15s 0.5s;
          
          &:before {
            transform: translate(-50%, 0) rotate(35deg) scaleX(0.6);
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(-35deg) scaleX(0.6);
          }
        }
      }
      
      &:nth-child(12) {
        button {
          transition: transform 0.35s 0.35s;
          
          &:before,
          &:after {
            transform-origin: 0% 0%;
            transition: transform 0.35s 0s;
          }
        }
      
        &:hover button {
          transform: rotate(-90deg);
          transition: transform 0.35s 0s;
          
          &:before {
            transform: translate(-50%, 0) rotate(-45deg) scaleX(0.8);
            transition: transform 0.35s 0.35s;
          }
          
          &:after {
            transform: translate(-50%, 0) rotate(45deg) scaleX(0.8);
            transition: transform 0.35s 0.35s;
          }
        }
      }
      
      
      &:nth-child(n+13) {
        & button {
          height: 30px;
          background: transparent;
          border-top: 1px solid;
          border-bottom: 1px solid;
          
          &:before,
          &:after {
            top: 50%;
            transform: translate(-50%, -50%);
          }
        }
      }
      
      &:nth-child(13) {
        &:hover button {
          border-color: transparent;
          
          &:before {
            transform: translate(-50%, -50%) rotate(45deg);
          }
          
          &:after {
            transform: translate(-50%, -50%) rotate(-45deg);
          }
        }
      }
      
      &:nth-child(14) {
        &:hover button {
          border-color: transparent;
          
          &:before {
            transform: translate(-50%, -50%) rotate(-45deg);
          }
          
          &:after {
            transform: translate(-50%, -50%) rotate(-135deg);
          }
        }
      }
      
      &:nth-child(15) {
        &:hover button {
          border-color: transparent;
          
          &:before {
            transform: translate(-50%, -50%) rotate(135deg);
          }
          
          &:after {
            transform: translate(-50%, -50%) rotate(-135deg);
          }
        }
      }
      
      &:nth-child(16) {
        button {
          &:before,
          &:after {
            transform-origin: 100% 0%;
          }
        }
      
        &:hover button {
          border-color: transparent;
          
          &:before {
            transform: translate(-50%, -50%) rotate(30deg) scaleX(0.7);
          }
          
          &:after {
            transform: translate(-50%, -50%) rotate(-30deg) scaleX(0.7);
          }
        }
      }
      
      &:nth-child(17) {
        button {
          transition: height 0.35s 0.35s, border-color 0.35s 0.35s;
          
          &:before,
          &:after {
            transform-origin: 50% 50%;
          }
        }
      
        &:hover button {
          height: 0;
          border-color: transparent;
          transition: all 0.35s 0s;
          
          &:before {
            transform: translate(-50%, -50%) rotate(45deg);
            transition-delay: 0.5s;
          }
          
          &:after {
            transform: translate(-50%, -50%) rotate(-45deg);
            transition-delay: 0.5s;
          }
        }
      }
      
      &:nth-child(18) {
        button {
          transition: height 0.35s 0.35s, border-color 0.35s 0.35s;
          
          &:before,
          &:after {
            transform-origin: 50% 50%;
          }
        }
      
        &:hover button {
          height: 0;
          border-color: transparent;
          transition: all 0.35s 0s;
          
          &:before {
            transform: translate(-50%, -50%) rotate(-45deg);
            transition-delay: 0.5s;
          }
          
          &:after {
            transform: translate(-50%, -50%) rotate(-135deg);
            transition-delay: 0.5s;
          }
        }
      }
      
      &:nth-child(19) {
        button {
          transition: height 0.35s 0.35s, border-color 0.35s 0.35s, transform 0.35s 0s;
          
          &:before,
          &:after {
            transform-origin: 50% 50%;
          }
        }
      
        &:hover button {
          height: 0;
          border-color: transparent;
          transform: rotate(135deg);
          transition: all 0.35s 0s, transform 0.35s 1s;
          
          &:before {
            transform: translate(-50%, -50%) rotate(90deg);
            transition-delay: 0.5s;
          }
        }
      }
      
      &:nth-child(20) {
        button {
          transition: height 0.35s 0.35s, border-color 0.35s 0.35s, transform 0.35s 0s;
          
          &:before,
          &:after {
            transform: translate(0, -50%);
            width: 50%;
            height: 0;
            background: transparent;
            border-top: 1px solid;
          }
          
          &:before {
            left: 0;
            border-right: 1px solid;
          }
          
          &:after {
            left: auto;
            right: 0;
            border-left: 1px solid;
          }
        }
      
        &:hover button {
          height: 0;
          border-color: transparent;
          transform: rotate(360deg);
          transition: all 0.35s 0s, transform 0.7s 0s;
          
          &:before,
          &:after {
            height: 25px;
            transition: height 0.35s 0.35s, transform 0.35s 0.35s;
          }
          
          &:before {
            transform: translate(-6px, -50%) rotate(45deg);
          }
          &:after {
            transform: translate(6px, -50%) rotate(-45deg);
          }
        }
      }
    }
    
    &:after {
      display: block;
      clear: both;
      content: "";
      position: relative;
    }
  }
}