* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: "Acme", monospace;
}

body {
  height: 100vh;
  width: 100vw;
  background-image: url("Images/background.jpg");
  background-size: cover;
  background-position: center;
  position: relative;
}

.open {
  width: (100%);
  display: block;
  justify-content: center;
  align-items: center;
  margin-top: 100px;
}

.mainTag {
  color: #c5c5c5;
  font-weight: bolder;
}

.scoreDisplay {
 visibility: hidden;  
}

.welcome {
  color: #ffffff;
  font-weight: 800;
  width: 70%;
  margin: auto;
  margin-bottom: 20px;
}

.btn-handle {
  background-color: #2580b3;
  color: #fff;
}

.btn-handle:hover {
  background-color: #ffffff;
}

.headTag {
margin: auto;
}

.headTag,
.points > p {
  color: #c5c5c5;
  font-weight: bolder;
}

#point {
  font-weight: 1300;
}

.memory-game {
  width: calc(25% - 10px);
  height: calc(25% - 10px);
  margin: auto;
  display: flex;
  flex-wrap: wrap;
  perspective: 1000px;
  z-index: -1;
}

.memory-card {
  width: calc(25% - 10px);
  height: calc(25% - 10px);
  margin: 5px;
  position: relative;
  transform: scale(1);
  transform-style: preserve-3d;
  transition: transform 0.5s;
  border-radius: 0px;
<!--  background-color: #ffffff; -->
}

.memory-card:active {
  transform: scale(0.97);
  transition: transform 0.2s;
}

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

.front-face,
.back-face {
  width: 100%;
  height: 100%;
  padding: 0px;
  position: absolute;
  border-radius: 0px;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;  /* Safari */
}

.front-face {
  transform: rotateY(180deg);
}

#winning-picture {
  width: 100%;
  height: auto;
}

#title-picture {
  width: 100%;
}

#won {
  visibility: hidden;
  border-radius: 15px;
  background: #b7e0ff;
  margin: auto;
  position: absolute;
  text-align: center;
  left: 50%;
  top: 20px;
  margin-right: -50%;
  transform: translate(-50%,0);
  display: flex;   
  flex-wrap: wrap;
  z-index: 3;
  border: 5px solid #ffffff;
  perspective: 1000px;
}

#won > h1,
#won p {
width: 100%;
  margin-top: 15px;
  font-weight: bolder;
  text-align: center;
  color: #333333;
}

#playAgain {
  border-radius: 5px;
  background: #2580b3;
  position: relative;
  top: 10px;
  left: 50%;
  transform: translate(-50%,0%);
  color: #fff;
  background-color: #76c3f0; 

}

#playAgain:hover {
  color: #76c3f0;
  background-color: #fff; 
}

/*LARGE DEVICES*/
@media (min-width: 992px) {
  .mainTag {
    font-size: 80px;
    margin-top: 60px;
  }

  .welcome {
    font-size: 35px;
  }

  .btn-handle {
    font-size: 40px;
    padding: 10px 20px;
    border-radius: 10px;
  }

  .memory-game {
    width: 640px;
    height: 640px;
  }

  .front-face,
  .back-face {
    padding: 0px;
  }
  #won {
    padding: 25px;
    top: 150px;
    width: 680px;
  }

  .headTag {
    font-size: 70px;
    width: 680px;
  }

  .points > p,
  #won > h1,
  #won p,
  #playAgain {
  font-size: 35px;
  }
}

/*medium devices*/

@media (min-width: 768px) and (max-width: 991px) {
  .mainTag {
    font-size: 75px;
    margin-top: 60px;
  }

  .welcome {
    font-size: 30px;
  }

  .btn-handle {
    font-size: 35px;
    padding: 10px 20px;
    border-radius: 10px;
  }

  .memory-game {
    width: 620px;
    height: 620px;
  }

  .front-face,
  .back-face {
    padding: 0px;
  }

  #won {
    padding: 25px;
    top: 145px;
    width: 660px;
  }

  .headTag {
    font-size: 70px;
    width: 660px;
  }

  .points > p,
  #won > h1,
  #won p,
  #playAgain {
    font-size: 35px;
  }
}

/*SMALL DEVICES*/
@media (min-width: 576px) and (max-width: 767px) {
  .mainTag {
    font-size: 60px;
    margin-top: 50px;
  }

  .welcome {
    font-size: 25px;
  }

  .btn-handle {
    font-size: 30px;
    padding: 10px 20px;
    border-radius: 10px;
  }

  .memory-game {
    width: 480px;
    height: 480px;
  }
  .front-face,
  .back-face {
    padding: 0px;
  }

  #won {
    padding: 18px;
    top: 115px;
    width: 520px;
  }

  .headTag {
    font-size: 50px;
    width: 520px;
  }

  .points > p,
  #won > h1,
  #won p,
  #playAgain {
    font-size: 30px;
  }
}

/*EXTRA SMALL DEVICES*/
@media (min-width: 378px) and (max-width: 575px) {
  .mainTag {
    font-size: 45px;
    margin-top: 45px;
  }

  .welcome {
    font-size: 25px;
  }

  .btn-handle {
    font-size: 30px;
    padding: 10px 20px;
    border-radius: 10px;
  }

  .memory-game {
    width: 380px;
    height: 380px;
  }
  .front-face,
  .back-face {
    padding: 0px;
  }

  #won {
    padding: 15px;
    top: 93px;
    width: 420px;
  }

  .headTag {
    font-size: 45px;
    width: 420px;
  }

  .points > p,
  #won > h1,
  #won p,
  #playAgain {
    font-size: 25px;
  }
}

/*X-EXTRA SMALL DEVICES*/
@media (max-width: 377px) {
  .mainTag {
    font-size: 45px;
    margin-top: 40px;
  }

  .welcome {
    font-size: 20px;
  }

  .btn-handle {
    font-size: 30px;
    padding: 10px 20px;
    border-radius: 10px;
  }

  .memory-game {
    width: 340px;
    height: 340px;
  }

  .front-face,
  .back-face {
    padding: 0px;
  }

  #won {
    padding: 8px;
    top: 84px;
    width: 380px;
  }

  .headTag {
    font-size: 40px;
    width: 380px;
  }

  .points > p,
  #won > h1,
  #won p,
  #playAgain {
    font-size: 25px;
  }
}