* {
 margin: 0;
 padding: 0;
 -webkit-box-sizing: border-box;
         box-sizing: border-box;
}

body {
 background-color: lightcoral;
 background-repeat: no-repeat;
 background-size: cover;
 font-family: Arial, Helvetica, sans-serif;
}

.puzzle__container {
 width: 100%;
 max-width: 1600px;
 margin: 0 auto;
}

.puzzle__title {
 margin: 5px auto;
 padding: 10px;
 text-align: center;
}

/* choosing imgs */
/**************************/
.puzzle__choiceImgBox {
 display: -webkit-box;
 display: -ms-flexbox;
 display: flex;
 -ms-flex-wrap: wrap;
     flex-wrap: wrap;
 -webkit-box-pack: space-evenly;
     -ms-flex-pack: space-evenly;
         justify-content: space-evenly;
 -webkit-box-align: center;
     -ms-flex-align: center;
         align-items: center;
 height: 360px;
 width: 100%;
}

.puzzle__choiceBtn {
 -ms-flex-preferred-size: 30%;
     flex-basis: 30%;
 height: 30%;
 position: relative;
 border-radius: 5px;
 border: 2px solid purple;
 overflow: hidden;
 cursor: pointer;
 -webkit-transform: scale(0.9);
     -ms-transform: scale(0.9);
         transform: scale(0.9);
 -webkit-transition: 0.2s;
 -o-transition: 0.2s;
 transition: 0.2s;
}

.puzzle__choiceBtn:hover {
 -webkit-transform: scale(1);
     -ms-transform: scale(1);
         transform: scale(1);
}

.puzzle__choiceBtn img {
 position: absolute;
 top: 50%;
 left: 50%;
 -webkit-transform: translate(-50%, -50%);
     -ms-transform: translate(-50%, -50%);
         transform: translate(-50%, -50%);
 min-width: 100%;
 min-height: 100%;
 pointer-events: none;
}

/*******************************************************/
/* The mainBoard */
.puzzle__mainBoard {
 display: grid;
 grid-template-columns: repeat(5, 1fr);
 grid-template-rows: repeat(5, 1fr);
 margin: 0 auto;
 max-width: 800px;
}

.puzzle__mBoardElement {
 position: relative;
 /* border: 2px solid black; */
 -webkit-box-shadow: 0 0 0px 4px black;
         box-shadow: 0 0 0px 4px black;
 height: 50px;

}

.puzzle__mBoardElement img {
 position: absolute;
 left: 50%;
 top: 50%;
 -webkit-transform: translate(-50%, -50%);
     -ms-transform: translate(-50%, -50%);
         transform: translate(-50%, -50%);
 width: 100%;
 cursor: pointer;
}

/* The chooseBoard */
.puzzle__chooseBoard {
 display: -webkit-box;
 display: -ms-flexbox;
 display: flex;
 width: 100%;
 -ms-flex-wrap: wrap;
     flex-wrap: wrap;
 -webkit-box-pack: center;
     -ms-flex-pack: center;
         justify-content: center;
 -webkit-box-align: center;
     -ms-flex-align: center;
         align-items: center;
 max-width: 1100px;
 height: auto;
 margin: 0 auto;
}

.puzzle__chooseElement {
 position: relative;
 height: 48px;
 -ms-flex-preferred-size: 20%;
     flex-basis: 20%;
 border-radius: 5px;
 border: 2px solid black;
 -webkit-transform: scale(0.9);
     -ms-transform: scale(0.9);
         transform: scale(0.9);
 -webkit-transition: 0.2s;
 -o-transition: 0.2s;
 transition: 0.2s;
 cursor: pointer;
}

.puzzle__chooseElement:hover {
 -webkit-transform: scale(1);
     -ms-transform: scale(1);
         transform: scale(1);
}

.puzzle__chooseElement img {
 position: absolute;
 left: 50%;
 top: 50%;
 -webkit-transform: translate(-50%, -50%);
     -ms-transform: translate(-50%, -50%);
         transform: translate(-50%, -50%);
 height: 100%;
 margin: 0 auto;
}

@media(min-width:412px) {
 .puzzle__mBoardElement {
  height: 56px;
 }
}

@media(min-width:460px) {
 .puzzle__mBoardElement {
  height: 62px;
 }
}

@media(min-width:520px) {
 .puzzle__mBoardElement {
  height: 72px;
 }

 .puzzle__choiceImgBox {
  height: 350px;
 }

 .puzzle__choiceBtn {
  height: 30%;
 }
}

@media(min-width:576px) {
 .puzzle__mBoardElement {
  height: 79px;
 }
}

@media(min-width:640px) {
 .puzzle__choiceBtn {
  -ms-flex-preferred-size: 30%;
      flex-basis: 30%;
  height: 30%;
 }

 .puzzle__mBoardElement {
  height: 88px;
 }

 .puzzle__chooseBoard {
  height: 340px;
 }

 .puzzle__chooseElement {
  height: 20%;
  -ms-flex-preferred-size: 15%;
      flex-basis: 15%;
 }
}

@media(min-width:768px) {
 .puzzle__choiceImgBox {
  height: 350px;
 }

 .puzzle__mBoardElement {
  height: 101px;
 }
}

@media(min-width:935px) {
 .puzzle__choiceBtn {
  -ms-flex-preferred-size: 20%;
      flex-basis: 20%;
  height: 40%;
 }

 .puzzle__mBoardElement {
  height: 107px;
 }

 .puzzle__chooseBoard {
  height: 200px;
 }

 .puzzle__chooseElement {
  height: 32%;
  -ms-flex-preferred-size: 9%;
      flex-basis: 9%;
 }
}

@media(min-width:1280px) {
 .puzzle__container {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: start;
      -ms-flex-pack: start;
          justify-content: flex-start;
  min-height: 100vh;
 }

 .puzzle__box {
  -webkit-box-flex: 1;
      -ms-flex-positive: 1;
          flex-grow: 1;
  height: 100vh;
 }

 .puzzle__choice {
  height: 100vh;
 }

 .puzzle__choiceImgBox {
  height: 90%;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
      -ms-flex-direction: column;
          flex-direction: column;
 }

 .puzzle__choiceBtn {
  -ms-flex-preferred-size: 10%;
      flex-basis: 10%;
  width: 50%;
 }
}