:root {
    --main-white: #ffffff;
    --main-black: #000000;
    --main-purple: #431197;
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    display: flex;
    min-height: 100vh;
    align-items: center;
    justify-content: center;
    background-color: var(--main-black);
    font-family: Arial, Helvetica, sans-serif;
  }
  
  .wrapper {
    padding: 25px;
    border-radius: 10px;
    background-color: var(--main-purple);
  }

  .cards, .card, .view {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .cards {
    height: 500px;
    width: 500px;
    flex-wrap: wrap;
    justify-content: space-between;
  }

  .cards .card {
    cursor: pointer;
    list-style: none;
    user-select: none;
    position: relative;
    perspective: 1000px;
    transform-style: preserve-3d;
    height: calc(100% / 4 - 10px);
    width: calc(100% / 4 - 10px);
  }

  .card.shake {
    animation: shake 0.35s ease-in-out;
  }

  @keyframes shake {
    0%, 100% {
        transform: translateX(0);
    }

    20% {
        transform: translateX(-13px);
    }

    40% {
        transform: translateX(13px);
    }

    60% {
        transform: translateX(-8px);
    }

    80% {
        transform: translateX(8px);
    }
  }

  .card .view {
    width: 100%;
    height: 100%;
    position: absolute;
    border-radius: 7px;
    background-color: var(--main-white);
    pointer-events: none;
    backface-visibility: hidden;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    transition: transform 0.25s linear;
  }

  .card .front-view img {
    width: 92px;
  }

  .card .back-view img {
    max-width: 75px;
  }

  .card .back-view {
    transform: rotateY(-180deg);
  }

  .card.flip .back-view {
    transform: rotateY(0);
  }

  .card.flip .front-view {
    transform: rotateY(180deg);
  }

  @media screen and (max-width: 700px) {
    .cards {
        height: 350px;
        width: 350px;
    }

    .card .front-view img {
        width: 17px;
    }

    .card .back-view img {
        max-width: 40px;
    }
  }

  @media screen and (max-width: 530px) {
    .cards {
        height: 300px;
        width: 300px;
    }

    .card .front-view img {
        width: 15px;
    }

    .card .back-view img {
        max-width: 35px;
    }
  }