<main>
  <div class="grid"></div>
  <div class="grid"></div>
  <div class="grid"></div>
  <div class="grid"></div>
</main>
<h1></h1>
<span id="shadow"></span>
<div id="line"></div>
<div id="double-circle"></div>

body {
  min-height: 100vh;
  overflow: hidden;
}

main {
  position: relative;
  display: grid;
  width: 100vw;
  height: 100vh;
  grid-template-columns: repeat(2, 1fr);
  grid-template-rows: repeat(2, 1fr);
  font-family: Helvetica;
}

.grid {
  outline: 10px solid #2d2d2d;
  background-color: #d8c292;
  animation: background 1.5s linear infinite;
}

#shadow {
  position: absolute;
  z-index: 1;
  background: transparent;
  top: 50%;
  left: 50%;
  width: 100vw;
  height: 100vh;
  transform: translate(-50%, -50%);
  box-shadow: inset 0 0 200px #000;

  &:before {
    position: absolute;
    content: '';
    z-index: 50;
    background: transparent;
    top: 50%;
    left: 50%;
    width: 100%;
    height: 100%;
    transform: translate(-50%, -50%);
    box-shadow: inset 0 0 200px #000;
  }
  
    &:after {
    position: absolute;
    content: '';
    z-index: 50;
    background: transparent;
    top: 50%;
    left: 50%;
    width: 100%;
    height: 100%;
    transform: translate(-50%, -50%);
    box-shadow: inset 0 0 200px #000;
  }
}

#double-circle {
  position: absolute;
  z-index: 150;
  padding: 2rem;
  top: 50%;
  left: 50%;
  width: 500px;
  height: 500px;
  background: transparent;
  transform: translate(-50%, -50%);
  border: 20px solid #f2f3f4;
  box-shadow: 5px 5px 25px #f2f3f4;
  border-radius: 50%;

  &:before {
    position: absolute;
    content: "";
    z-index: 150;
    padding: 1rem;
    top: 50%;
    left: 50%;
    width: 440px;
    height: 440px;
    background: transparent;
    transform: translate(-50%, -50%);
    border: 20px solid #f2f3f4;
    box-shadow: 5px 5px 25px #f2f3f4;
    border-radius: 50%;
  }
}

#line {
  position: absolute;
  z-index: 160;
  top: 49%;
  left: 49%;
  width: 10px;
  height: 1000px;
  background-color: #2d2d2d;
  transform-origin: 50% 0;
  animation: rotate 1s linear infinite;
}

h1 {
  position: absolute;
  z-index: 1000;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 32rem;
  font-weight: 900;
  color: #2d2d2d;
  text-shadow: 4px 2px 15px #2d2d2d;

  &:before {
    position: absolute;
    z-index: 1000;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    content: counter(count);
    animation: counter 11s linear backwards infinite;
    counter-reset: count;
  }
}

@keyframes rotate {
  0% {
    transform: rotate(0deg);
  }

  100% {
    transform: rotate(360deg);
  }
}

@keyframes counter {
  0% {
    counter-increment: count 10;
  }
  10% {
    counter-increment: count 9;
  }
  20% {
    counter-increment: count 8;
  }
  30% {
    counter-increment: count 7;
  }
  40% {
    counter-increment: count 6;
  }
  50% {
    counter-increment: count 5;
  }
  60% {
    counter-increment: count 4;
  }
  70% {
    counter-increment: count 3;
  }
  80% {
    counter-increment: count 2;
  }
  90% {
    counter-increment: count 1;
  }
  100% {
    counter-increment: count 0;
  }
}

@keyframes background {
  from {
    background-color: darken(#d8c292, 30%);
  }
  
  to {
    background-color: #d8c292;
  }
}