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

.canvas , #container {
    display: flex;
    flex-direction: column;
}

#container {
    width: 600px;
    margin: 15px auto;
    text-align: center;
    justify-content: space-between;
    align-items: center;
}

section {
    margin-bottom: 15px;
    /* border: 1px solid black; */
    position: relative;
}

#background {
    width: 98%;
    height: 300px;
    position: absolute;
    top: 15px;
    left: 0;
    background-position: center;
    background-repeat: no-repeat;
    background-size: contain;
    opacity: 0.3;
}

.canvas {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: space-around;
}


.canvas p {
    width: 140px;
    height: 140px;
    line-height: 140px;
    color: #aa6600;
    background-color: #33CCFF;
    font-size: 70px;
    text-align: center;
    border-radius: 10px;
    box-shadow: 1px 1px 3px 1px #555;
    z-index: 5;
    margin: 30px 15px;
}

.canvas:hover , #btn:hover {
    cursor: pointer;
}

.mark{
    animation: mark 0.5s linear infinite;
}

@keyframes mark {
    0% { transform: scale(1);  }
    50% { transform: scale(1.1);  }
    100% { transform: scale(1);  }
}


#info {
    border: 1px solid black;
    width: 100%;
    height: 55px;
    border-radius: 10px;
    background-color: lightgreen;
    box-shadow: 1px 1px 5px 1px #aaa;
    overflow: hidden;
}

#info span {
    height: 100%;
    font-size: 40px;
    line-height: 55px;
    text-align: center;
    padding: 0px 10px;
}

.selected {
    animation: disappear 0.5s linear forwards;
}
@keyframes disappear {
    to  { 
            transform: scale(1.3); 
            opacity: 0;  
        }
}

.appear {
    animation: appear 1s linear forwards;
}
@keyframes appear {
    to  { 
            opacity: 1;  
        }
}


#btn-container {
    height: 90px;
    bottom: 0px;
    position: absolute;
    z-index: 10;
}


img {
    width: 50px;
    height: 50px;
}

#btn {
    width: 70px;
    height: 70px;
    margin: 0px auto;
    border: none;
    border-radius: 50%;
    background-color: lightblue;
    z-index: 12;
}

#btn:focus {
    border: none;
    outline: none;
}

@media only screen and (max-width: 600px) 
{
    #container {
      margin-top: 5px;
      width: 300px;
    }

    section {
        margin-bottom: 15px;
        /* border: 1px solid black; */
        position: relative;
    }

    #info {
      margin-top: 5px;
      margin-bottom: 25px;
    }

    #info span {
      padding: 0px 10px;
      font-size: 35px;
    }

    .canvas p {
      width: 90px;
      height:90px;
      font-size: 55px;
      line-height: 90px;
      margin: 15px 15px;
    }
} /* end of media query */