.zoomIn {
    -webkit-animation-name: zoomIn;
    animation-name: zoomIn;
    -webkit-animation-duration: 1s;
    animation-duration: 1s;
    -webkit-animation-fill-mode: both;
    animation-fill-mode: both;
  }
  @-webkit-keyframes zoomIn {
    0% {
      opacity: 0;
      -webkit-transform: scale3d(0.3, 0.3, 0.3);
      transform: scale3d(0.3, 0.3, 0.3);
    }
    50% {
      opacity: 1;
    }
  }
  @keyframes zoomIn {
    0% {
      opacity: 0;
      -webkit-transform: scale3d(0.3, 0.3, 0.3);
      transform: scale3d(0.3, 0.3, 0.3);
    }
    50% {
      opacity: 1;
    }
  }
  
  .bounceIn {
    -webkit-animation-name: bounceIn;
    animation-name: bounceIn;
    -webkit-animation-duration: 0.75s;
    animation-duration: 0.75s;
    -webkit-animation-duration: 1s;
    animation-duration: 1s;
    -webkit-animation-fill-mode: both;
    animation-fill-mode: both;
  }
  @-webkit-keyframes bounceIn {
    0%,
    20%,
    40%,
    60%,
    80%,
    100% {
      -webkit-transition-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
      transition-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
    }
    0% {
      opacity: 0;
      -webkit-transform: scale3d(0.3, 0.3, 0.3);
      transform: scale3d(0.3, 0.3, 0.3);
    }
    20% {
      -webkit-transform: scale3d(1.1, 1.1, 1.1);
      transform: scale3d(1.1, 1.1, 1.1);
    }
    40% {
      -webkit-transform: scale3d(0.9, 0.9, 0.9);
      transform: scale3d(0.9, 0.9, 0.9);
    }
    60% {
      opacity: 1;
      -webkit-transform: scale3d(1.03, 1.03, 1.03);
      transform: scale3d(1.03, 1.03, 1.03);
    }
    80% {
      -webkit-transform: scale3d(0.97, 0.97, 0.97);
      transform: scale3d(0.97, 0.97, 0.97);
    }
    100% {
      opacity: 0;
      -webkit-transform: scale3d(1, 1, 1);
      transform: scale3d(1, 1, 1);
    }
  }
  @keyframes bounceIn {
    0%,
    20%,
    40%,
    60%,
    80%,
    100% {
      -webkit-transition-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
      -o-transition-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
      transition-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
    }
    0% {
      opacity: 0;
      -webkit-transform: scale3d(0.3, 0.3, 0.3);
      transform: scale3d(0.3, 0.3, 0.3);
    }
    20% {
      -webkit-transform: scale3d(1.1, 1.1, 1.1);
      transform: scale3d(1.1, 1.1, 1.1);
    }
    40% {
      -webkit-transform: scale3d(0.9, 0.9, 0.9);
      transform: scale3d(0.9, 0.9, 0.9);
    }
    60% {
      opacity: 1;
      -webkit-transform: scale3d(1.03, 1.03, 1.03);
      transform: scale3d(1.03, 1.03, 1.03);
    }
    80% {
      -webkit-transform: scale3d(0.97, 0.97, 0.97);
      transform: scale3d(0.97, 0.97, 0.97);
    }
    100% {
      opacity: 0;
      -webkit-transform: scale3d(1, 1, 1);
      transform: scale3d(1, 1, 1);
    }
  }
  
  @-webkit-keyframes rotate-center {
    0% {
      -webkit-transform: rotate(0);
      transform: rotate(0);
      opacity: 1;
    }
    100% {
      -webkit-transform: rotate(360deg);
      transform: rotate(360deg);
      opacity: 0;
    }
  }
  @keyframes rotate-center {
    0% {
      -webkit-transform: rotate(0);
      transform: rotate(0);
      opacity: 1;
    }
    100% {
      -webkit-transform: rotate(360deg);
      transform: rotate(360deg);
      opacity: 0;
    }
  }
  
  
  #playground {
    padding: 5px;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    /* width: 866px; */
    width: 500px;
    width: 30vw;
  
    max-width: 97%;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    background-color: rgba(255, 255, 255, 0.7);
    margin: auto;
    border-radius: 20px;
  }
  
  #playground > div {
    display: block;
    margin: 4px;
    /* height: 130px; */
    height: 10vw;

    position: relative;
    -webkit-box-flex: 1;
    -ms-flex: 1 0 11%;
    /* flex: 1 0 11%; */
    flex: 1 0 23%;
  
    background-color: transparent;
  }
  .card_back {
    background-color: lime;
    width: 99px;
    height: 140px;
  }
  .card_front {
    background-color: yellow;
    width: 99px;
    height: 140px;
  }
  
  /* #playground > .card1::before {
    
    } */
  
  /* .flip-card-back::before {
          font-size: 55px;
        font-family: 'Font Awesome 5 Free';
        font-weight: 900;
        position: absolute;
       top: 44px;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%)
    } */
  
  .card01100011011000010111001001100100 > .flip-card-inner > .flip-card-back {
    background-image: url("/tetnguyendan/assets/img/labai1.png");
  }
  .card01100001011100100110001100110100 > .flip-card-inner > .flip-card-back {
    background-image: url("/tetnguyendan/assets/img/labai2.png");
  }
  .card01100001011100100110101101001000 > .flip-card-inner > .flip-card-back {
    background-image: url("/tetnguyendan/assets/img/labai3.png");
  }
  .card01100011011001010110011001100100 > .flip-card-inner > .flip-card-back {
    background-image: url("/tetnguyendan/assets/img/labai4.png");
  }
  .card01100001011000100110100001100101 > .flip-card-inner > .flip-card-back {
    background-image: url("/tetnguyendan/assets/img/labai5.png");
  }
  .card01100011011001010111001101101101 > .flip-card-inner > .flip-card-back {
    background-image: url("/tetnguyendan/assets/img/labai6.png");
  }
  /* .card01100001011000100110100101101011 > .flip-card-inner > .flip-card-back {
    background-image: url("/assets/img/cards-7.png");
  }
  .card01101101011011100110010101101110 > .flip-card-inner > .flip-card-back {
    background-image: url("/assets/img/cards-8.png");
  }
  .card01111010010000001100010011000010 > .flip-card-inner > .flip-card-back {
    background-image: url("/assets/img/cards-9.png");
  }
  .card01100011011000010110011101101000 > .flip-card-inner > .flip-card-back {
    background-image: url("/assets/img/cards-10.png");
  }
  
  .card01100011011000010110100101100100 > .flip-card-inner > .flip-card-back {
    background-image: url("/assets/img/cards-11.png");
  }
  .card01100001011100100111001101110110 > .flip-card-inner > .flip-card-back {
    background-image: url("/assets/img/cards-12.png");
  } */
  
  div[class^="card"] {
    background-color: transparent;
    color: white;
    -webkit-perspective: 1000px;
    perspective: 1000px;
    border-radius: 15px;
  }
  
  .flip-card-front:hover {
    cursor: pointer;
    -webkit-box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2),
      0 6px 20px 0 rgba(0, 0, 0, 0.19);
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
    border-radius: 15px;
    background-color: transparent;
  
    /*   overflow: hidden; */
  }
  
  .flip-card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    -webkit-transition: -webkit-transform 0.7s;
    transition: -webkit-transform 0.7s;
    -o-transition: transform 0.7s;
    transition: transform 0.7s;
    transition: transform 0.7s, -webkit-transform 0.7s;
    -webkit-transform-style: preserve-3d;
    transform-style: preserve-3d;
  }
  
  /* Do an horizontal flip when you move the mouse over the flip box container */
  /* div[class^="card"]:hover .flip-card-inner {
      transform: rotateY(180deg);
    } */
  
  /* Do an horizontal flip when you move the mouse over the flip box container */
  .flip {
    -webkit-transform: rotateY(180deg);
    transform: rotateY(180deg);
  }
  
  .rotate {
    -webkit-animation: rotate-center 1s ease-in-out both;
    animation: rotate-center 1s ease-in-out both;
  }
  
  /* Position the front and back side */
  .flip-card-front,
  .flip-card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden; /* Safari */
    backface-visibility: hidden;
  }
  
  /* Style the front side (fallback if image is missing) */
  .flip-card-front {
    /*   background-color: #bbb; */
    background-image: url("/tetnguyendan/assets/img/labai.png");
    background-size: cover;
    border: 2px solid #fdc72b;
    border-radius: 15px;
    -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08),
      0 1px 2px rgba(0, 0, 0, 0.14);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.14);
  
    /*   background-color: white; */
  }
  
  .flip-card-front::after {
    content: "";
    display: block;
    height: 109%;
    width: 109%;
    background-color: transparent;
    border-radius: 15px;
  }
  
  /* Style the back side */
  .flip-card-back {
    border: 2px solid gray;
    border-radius: 15px;
    color: white;
    -webkit-transform: rotateY(180deg);
    transform: rotateY(180deg);
    background-position: center;
    background-repeat: no-repeat;
    border: 2px solid darkgray;
    background-color: #fff4d7;
    background-size: cover;
  }
  
  .combo-container {
    display: block;
    position: relative;
    width: 866px;
    max-width: 96%;
    margin: auto;
  }
  
  .header-flip {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    width: 866px;
    max-width: 96%;
    margin: auto;
    margin-top: 10px;
    margin-bottom: 10px;
    -webkit-box-pack: justify;
    -ms-flex-pack: justify;
    justify-content: space-between;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    padding: 0 5px;
  }
  
  .footer-flip {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    width: 30vw;
    margin: auto;
    margin-top: 10px;
    margin-bottom: 10px;
    -webkit-box-pack: justify;
    -ms-flex-pack: justify;
    justify-content: space-between;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    padding: 0 5px;
  }
  
  .counter {
    display: inline-block;
    color: #fdd257;
    color: #000;

    font-weight: bold;
  }
  
  button {
    display: inline-block;
    position: relative;
    padding: 5px;
  }
  
  .muteBtn {
    display: none;
  }
  
  .muteBtn + label {
    display: inline-block;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    cursor: pointer;
    background-size: cover;
    background-image: url("https://i.ibb.co/8xG9vgT/sound-mute-01.png");
  }
  
  .muteBtn:checked + label {
    border-radius: 50%;
    background-image: url("https://i.ibb.co/h7w6rmR/sound-mute-02.png");
  }
  
  .muteBtn:hover + label {
    border-radius: 50%;
    -webkit-box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2),
      0 6px 20px 0 rgba(0, 0, 0, 0.19);
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
  }
  
  .start-screen {
    display: block;
    position: absolute;
    top: 1vw;
    left: 35vw;
    width: 30vw;
    text-align: center;
    height: 31.5vw;
    background-color: rgb(223 223 223 / 34%);
    border-radius: 1vw;
  }
  
  .sSInside {
    position: absolute;
    width: 500px;
    max-width: 95%;
    height: 450px;
    max-height: 90%;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
  }
  
  .teacherTxt {
    position: relative;
    /* background-color: white; */
    border-radius: 5px;
    width: 100%;
    height: 100%;
    padding: 15px;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    text-align: justify;
    text-justify: inter-word;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
  }
  
  .teacherTxt::after {
    /* content: "";
    position: absolute;
    display: block;
    width: 0;
    z-index: 1;
    border-style: solid;
    border-width: 0 17px 17px 0;
    border-color: transparent white transparent transparent;
    bottom: -16px;
    left: 88%;
    margin-left: -10px; */
  }
  
  .teacherImg {
    height: 50%;
    width: auto;
    position: relative;
    right: 0;
    display: inline-block;
    float: right;
  }
  
  #finishScreen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: block;
  }
  
  .fSSmall {
    position: absolute;
    width: 270px;
    height: 199px;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
  }
  
  .fSImg {
    position: absolute;
    height: 230px;
    width: auto;
    top: -27px;
    left: -54px;
  }
  
  .fSWhite {
    position: absolute;
    width: 270px;
    height: 199px;
    background-color: white;
    left: 22px;
    border-radius: 5px;
  }
  
  .fSPiece1 {
    text-align: center;
    position: absolute;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    height: 55%;
    width: 68%;
    top: 0px;
    right: 0px;
    color: #003956;
    padding: 2px;
    padding-right: 5px;
  }
  
  .fSPiece1 > h1 {
    font-size: 20px;
    margin-bottom: 5px;
  }
  
  .fSPiece2 {
    position: absolute;
    height: 41%;
    width: 76%;
    background-color: #126d9b;
    bottom: 0px;
    right: 0px;
    border-radius: 30px 0 5px 0;
    color: white;
    padding: 5px;
    padding-left: 17px;
  }
  
  .orange {
    color: #ef8a3f;
    font-weight: bold;
  }
  
  .exitBtn {
    position: absolute;
    background-color: red;
    width: 30px;
    height: 30px;
    right: -15px;
    top: -15px;
    z-index: 7;
    text-align: center;
    color: white;
    font-weight: bold;
    border-radius: 50%;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    cursor: pointer;
  }
  
  .exitBtn2 {
    right: unset;
    top: -15px;
    left: -15px;
  }
  
  .exitBtn:hover {
    -webkit-box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2),
      0 6px 20px 0 rgba(0, 0, 0, 0.19);
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
  }
  
  #combo {
    /*   margin: auto;
      text-align: center; */
    position: absolute;
    top: 0;
    left: 0;
    z-index: 5;
    pointer-events: none;
  }
  
  .startButton {
    background-color: #fdd257;
    border-color: orange;
    border-radius: 5px;
    color: #723900;
    cursor: pointer;
    font-weight: bold;
  }
  
  .startButton:hover {
    background-color: orange;
    color: #2f4f4f;
  }
  
  button:focus {
    outline: none;
  }
  
  .noselect {
    -webkit-touch-callout: none; /* iOS Safari */
    -webkit-user-select: none; /* Safari */ /* Konqueror HTML */
    -moz-user-select: none; /* Old versions of Firefox */
    -ms-user-select: none; /* Internet Explorer/Edge */
    user-select: none; /* Non-prefixed version, currently
                                      supported by Chrome, Edge, Opera and Firefox */
  }
  
  .clearfix::after {
    content: "";
    clear: both;
    display: table;
  }
  
  .creditsBtn {
    position: absolute;
    bottom: 1%;
    right: 1%;
    background-color: #65c9d1;
    border-color: #116d9c;
    color: white;
  }
  
  .creditsBtn:hover {
    position: absolute;
    bottom: 1%;
    right: 1%;
    background-color: #2b9db1;
    border-color: #116d9c;
    color: white;
  }
  
  .info-screen {
    position: absolute;
    background-color: rgba(255, 255, 255, 0.8);
    bottom: 1%;
    right: 1%;
    border-radius: 5px;
    padding: 20px 10px;
    border: 1px solid #0c73b8;
    text-align: center;
  }
  
  .infoImg {
    display: block;
    margin: auto;
    padding: 4%;
  }
  
@media screen and (max-width: 1366px) {
    #playground{
        width: 31vw;
    }
  }

  @media screen and (max-width: 1320px) {
    #playground{
        width: 32vw;
    }
  }

  @media screen and (max-width: 1281px) {
    #playground{
        width: 33vw;
    }
    .start-screen {
        left: 34vw;
        width: 32vw;
    }
  }

  @media screen and (max-width: 1281px) {
    #playground{
        width: 34vw;
    }
    .start-screen {
        left: 33vw;
        width: 33vw;
    }
  }

  @media screen and (max-width: 1281px) {
    #playground{
        width: 36vw;
    }
    .start-screen {
        left: 33vw;
        width: 35vw;
    }
  }

  @media screen and (max-width: 1139px) {
    #playground{
        width: 38vw;
    }
    .start-screen {
        left: 32vw;
        width: 36vw;
    }
  }

  @media screen and (max-width: 1077px) {
    #playground{
        width: 40vw;
    }
    .start-screen {
        left: 31vw;
        width: 38vw;
    }
  }

  @media screen and (max-width: 1025px) {
    #playground{
        width: 45vw;
    }
    .start-screen {
        left: 28vw;
        width: 44vw;
    }
  }

  @media screen and (max-width: 910px) {
    #playground{
        width: 50vw;
    }
    .start-screen {
        left: 26vw;
        width: 48vw;
    }
  }

  @media screen and (max-width: 788px) {
    #playground{
        width: 55vw;
    }
    .start-screen {
        left: 24vw;
        width: 52vw;
    }
  }

  @media screen and (max-width: 768px) {
    #playground{
        width: 90vw;
    }
    #playground > div {
        height: 30vw;
    }
    .start-screen {
        left: 5vw;
        width: 90vw;
        height: 95vw;
        border-radius: 4vw;
    }

    .footer-flip {
        width: 90vw;
    }

    .counter {
        font-size: 4vw;
    }
  }