*, *:before, *:after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
}
a {
  color: inherit;
  text-decoration: underline;
}
@font-face {
  font-family: decade;
  src: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/decade.ttf');
}
@font-face {
  font-family: pt-reg;
  src: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/PT_Sans-Web-Regular.ttf');
}
@font-face {
  font-family: pfs-bold;
  src: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/PFSquareSansPro-Bold.otf');
}
@mixin mediaMinWidth($width) {
  @media (min-width: $width) {
    & {
      @content;
    }
  }
}
@mixin mediaMaxWidth($width) {
  @media (max-width: $width) {
    & {
      @content;
    }
  }
}
header {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 3em;
  padding: 0.5em;
  @include mediaMinWidth(48em) {
    height: 5em;
    padding: 1em;
  }
  background-color: #fff;
  z-index: 150;
  
  nav {
    
    ul {
      list-style-type: none;
      text-align: right;
      
      li {
        display: inline-block;
        padding: 0.1em;
        font-size: 1em;
        border: 0.1em solid #000;
        margin-right: 0.2em;
        @include mediaMinWidth(48em) {
          font-size: 1.5em;
          padding: 0.2em;
          border: 0.2em solid #000;
          margin-right: 0.5em;
        }
        font-family: pfs-bold, sans-serif;
        text-transform: uppercase;
        cursor: pointer;
        transition: color, background-color 0.4s;
        
        &.active {
          background-color: #000;
          color: #fff;
        }
        
        &:hover {
          background-color: #000;
          color: #fff;
        }
      }
    }
    
    &.in-action {
      ul {
        li {
          opacity: 0.4;
          user-select: none;
        }
      }
    }
  }
}
section {
  position: absolute;
  top: 3em;
  @include mediaMinWidth(48em) {
    top: 5em;
  }
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 50;
  
  .content {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    @include mediaMinWidth(48em) {
      width: 40%;
    }
    z-index: 100;
    padding: 2em;
    overflow-y: auto;
    background-color: rgba(255, 255, 255, 0.8);
    
    .inner {
      display: none;
      
      &.active {
        display: block;
        animation: showTextBlock 1s;
      }
      
      h1 {
        font-size: 2em;
        margin-bottom: 1em;
        text-transform: uppercase;
        font-family: decade, sans-serif;
      }
      
      p {
        font-size: 1.25em;
        margin-bottom: 0.75em;
        font-family: pt-reg, sans-serif;
      }
    }
  }
  
  .backgrounds {
    
    .bg {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-size: cover;
      transition: 1.5s;
      will-change: transform;
      z-index: 60;
      
      &.iron {
        background-image: url('http://i.imgur.com/PbV1Grl.jpg');
        transform: translateX(-100%);
      }
      &.cap {
        background-image: url('http://i.imgur.com/VWYl1EC.jpg');
        transform: translateY(-100%);
      }
      &.bw {
        background-image: url('http://i.imgur.com/ga3BiDw.jpg');
        transform: translateX(100%);
      }
      &.thor {
        background-image: url('http://i.imgur.com/jAY4044.jpg');
        transform: translateY(100%);
      }
      
      &.active {
        transform: translateZ(0);
        z-index: 70;
      }
      
      &.fast {
        transition-duration: 0s;
      }
    }
  }
}
@keyframes showTextBlock {
  0% {
    opacity: 0;
    transform: scale(0.5);
  }
  80% {
    opacity: 1;
    transform: scale(1.05);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}