* {
  box-sizing: border-box;
}

.memory-board {
  margin: 100px auto;

  background-color: #f0f0f0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  width: fit-content;
  /*  flex-wrap: wrap; */
  justify-content: center;
  align-items: center;
  border-radius: 10px;
  box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.2);
}

.card {
  background-color: #ffff99;
  width: 300px;
  height: 210px;
  cursor: pointer;
  border: 1px solid #cccccc;
  border-radius: 1rem;
  margin: 3px;

  filter: drop-shadow(0 0 0.75rem rgba(0, 0, 0, 0.2));
  background-color: #00b7ff;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='540' height='450' viewBox='0 0 1080 900'%3E%3Cg fill-opacity='.1'%3E%3Cpolygon fill='%23444' points='90 150 0 300 180 300'/%3E%3Cpolygon points='90 150 180 0 0 0'/%3E%3Cpolygon fill='%23AAA' points='270 150 360 0 180 0'/%3E%3Cpolygon fill='%23DDD' points='450 150 360 300 540 300'/%3E%3Cpolygon fill='%23999' points='450 150 540 0 360 0'/%3E%3Cpolygon points='630 150 540 300 720 300'/%3E%3Cpolygon fill='%23DDD' points='630 150 720 0 540 0'/%3E%3Cpolygon fill='%23444' points='810 150 720 300 900 300'/%3E%3Cpolygon fill='%23FFF' points='810 150 900 0 720 0'/%3E%3Cpolygon fill='%23DDD' points='990 150 900 300 1080 300'/%3E%3Cpolygon fill='%23444' points='990 150 1080 0 900 0'/%3E%3Cpolygon fill='%23DDD' points='90 450 0 600 180 600'/%3E%3Cpolygon points='90 450 180 300 0 300'/%3E%3Cpolygon fill='%23666' points='270 450 180 600 360 600'/%3E%3Cpolygon fill='%23AAA' points='270 450 360 300 180 300'/%3E%3Cpolygon fill='%23DDD' points='450 450 360 600 540 600'/%3E%3Cpolygon fill='%23999' points='450 450 540 300 360 300'/%3E%3Cpolygon fill='%23999' points='630 450 540 600 720 600'/%3E%3Cpolygon fill='%23FFF' points='630 450 720 300 540 300'/%3E%3Cpolygon points='810 450 720 600 900 600'/%3E%3Cpolygon fill='%23DDD' points='810 450 900 300 720 300'/%3E%3Cpolygon fill='%23AAA' points='990 450 900 600 1080 600'/%3E%3Cpolygon fill='%23444' points='990 450 1080 300 900 300'/%3E%3Cpolygon fill='%23222' points='90 750 0 900 180 900'/%3E%3Cpolygon points='270 750 180 900 360 900'/%3E%3Cpolygon fill='%23DDD' points='270 750 360 600 180 600'/%3E%3Cpolygon points='450 750 540 600 360 600'/%3E%3Cpolygon points='630 750 540 900 720 900'/%3E%3Cpolygon fill='%23444' points='630 750 720 600 540 600'/%3E%3Cpolygon fill='%23AAA' points='810 750 720 900 900 900'/%3E%3Cpolygon fill='%23666' points='810 750 900 600 720 600'/%3E%3Cpolygon fill='%23999' points='990 750 900 900 1080 900'/%3E%3Cpolygon fill='%23999' points='180 0 90 150 270 150'/%3E%3Cpolygon fill='%23444' points='360 0 270 150 450 150'/%3E%3Cpolygon fill='%23FFF' points='540 0 450 150 630 150'/%3E%3Cpolygon points='900 0 810 150 990 150'/%3E%3Cpolygon fill='%23222' points='0 300 -90 450 90 450'/%3E%3Cpolygon fill='%23FFF' points='0 300 90 150 -90 150'/%3E%3Cpolygon fill='%23FFF' points='180 300 90 450 270 450'/%3E%3Cpolygon fill='%23666' points='180 300 270 150 90 150'/%3E%3Cpolygon fill='%23222' points='360 300 270 450 450 450'/%3E%3Cpolygon fill='%23FFF' points='360 300 450 150 270 150'/%3E%3Cpolygon fill='%23444' points='540 300 450 450 630 450'/%3E%3Cpolygon fill='%23222' points='540 300 630 150 450 150'/%3E%3Cpolygon fill='%23AAA' points='720 300 630 450 810 450'/%3E%3Cpolygon fill='%23666' points='720 300 810 150 630 150'/%3E%3Cpolygon fill='%23FFF' points='900 300 810 450 990 450'/%3E%3Cpolygon fill='%23999' points='900 300 990 150 810 150'/%3E%3Cpolygon points='0 600 -90 750 90 750'/%3E%3Cpolygon fill='%23666' points='0 600 90 450 -90 450'/%3E%3Cpolygon fill='%23AAA' points='180 600 90 750 270 750'/%3E%3Cpolygon fill='%23444' points='180 600 270 450 90 450'/%3E%3Cpolygon fill='%23444' points='360 600 270 750 450 750'/%3E%3Cpolygon fill='%23999' points='360 600 450 450 270 450'/%3E%3Cpolygon fill='%23666' points='540 600 630 450 450 450'/%3E%3Cpolygon fill='%23222' points='720 600 630 750 810 750'/%3E%3Cpolygon fill='%23FFF' points='900 600 810 750 990 750'/%3E%3Cpolygon fill='%23222' points='900 600 990 450 810 450'/%3E%3Cpolygon fill='%23DDD' points='0 900 90 750 -90 750'/%3E%3Cpolygon fill='%23444' points='180 900 270 750 90 750'/%3E%3Cpolygon fill='%23FFF' points='360 900 450 750 270 750'/%3E%3Cpolygon fill='%23AAA' points='540 900 630 750 450 750'/%3E%3Cpolygon fill='%23FFF' points='720 900 810 750 630 750'/%3E%3Cpolygon fill='%23222' points='900 900 990 750 810 750'/%3E%3Cpolygon fill='%23222' points='1080 300 990 450 1170 450'/%3E%3Cpolygon fill='%23FFF' points='1080 300 1170 150 990 150'/%3E%3Cpolygon points='1080 600 990 750 1170 750'/%3E%3Cpolygon fill='%23666' points='1080 600 1170 450 990 450'/%3E%3Cpolygon fill='%23DDD' points='1080 900 1170 750 990 750'/%3E%3C/g%3E%3C/svg%3E");
}

#start-button {
  position: absolute;
  top: 80%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 20px 40px;
  font-size: 18px;
  border-radius: 10px;
  background-color: #4caf50;
  border: none;
  color: white;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  cursor: pointer;
  z-index: 2;
}

#restart-button {
  position: absolute;
  top: 80%;
  right: 38%;
  transform: translate(-50%, -50%);
  padding: 20px 40px;
  font-size: 18px;
  border-radius: 10px;
  background-color: #4caf50;
  border: none;
  color: white;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  cursor: pointer;
  z-index: 2;
}

.back {
  background: #d8d8d8;
  /* box-shadow: 15px 15px 10px #999; */
}

.image1 {
  background: transparent url("/dog.png") 0 0 no-repeat;

  animation: run 1s steps(10) infinite;
}

#winner-message {
  display: none;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 60px;
  color: #d32f2f;
  padding: 0px;
  z-index: 1000;
  animation: slideIn 3s forwards, flash 0.5s infinite 3s;
}

@keyframes slideIn {
  0% {
    left: -50%;
  }
  100% {
    left: 50%;
  }
}

@keyframes flash {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0;
  }
}

@keyframes run {
  100% {
    background-position: -6040px, 0;
  }
}

.image2 {
  background: transparent url("/bird.png") 0 0 no-repeat;

  animation: fly 1s steps(10) infinite;
}

@keyframes fly {
  100% {
    background-position: -2790px, 0;
  }
}

.image3 {
  background: transparent url("/spider.png") 0 0 no-repeat;

  animation: attack 1s steps(2) infinite;
}
@keyframes attack {
  100% {
    background-position: -3000px, 0;
  }
}

.image4 {
  background: transparent url("/bug.png") 0 0 no-repeat;

  animation: fly 1s steps(10) infinite;
}