style.css
body {
    margin: 0;
    padding: 5px;
    background-color: #262626;
    user-select: none;
    font-family: 'Sarabun', sans-serif;
}

i {
    color: red;
    margin: 0px 2px 0px 2px;
}

.tab,
#status {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    margin: auto;
    background-color: white;
    border-radius: 10px;
    z-index: 1;
    width: 330px;
    height: 370px;
    padding: 10px;
    box-sizing: border-box;
    transition-duration: 150ms;
}

img {
    display: inline-block;
    position: relative;
    height: 80px;
    width: 80px;
    border-radius: 10px;
    top: 20px;
}

h3 {
    display: inline-block;
    color: dimgray;
    font-family: 'Press Start 2P', cursive;
    font-size: 20px;
    margin: 2px;
}

#info {
    display: block;
    position: relative;
    font-family: 'Sarabun', sans-serif;
    margin: 15px;
    margin-top: 25px;
}

#easy,
#hard,
#impossible {
    display: block;
    position: relative;
    padding: 12px;
    font-family: 'Press Start 2P', cursive;
    background-color: #efefef;
    border: 3px dashed #262626;
    font-size: 15px;
    text-align: center;
    margin: 10px;
}

#status {
    font-family: 'Press Start 2P', cursive;
    height: 200px;
    visibility: hidden;
    transition-duration: 100ms;
}

#result {
    font-size: 30px;
    margin: 20px 10px 10px 10px;
}

button {
    padding: 20px;
    position: relative;
    outline: none;
    border: 3px dashed #262626;
    border-radius: 10px;
    background-color: green;
    color: white;
    font-family: 'Press Start 2P', cursive;
    font-size: 18px;
    margin: 8px;
    margin-top: 25px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 3px 5px rgba(0, 0, 0, 0.3);
}

button:active {
    transform: scale(0.85);
    box-shadow: 0px 0px 0px gray;
}

#canvas {
    position: absolute;
    margin: auto;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background-color: dimgray;
    border: 4px solid white;
    box-sizing: border-box;
    z-index: 1;
}

@keyframes pop {
    0% {
        transform: scale(0.8);
    }
    34% {
        transform: scale(1);
    }
    66% {
        transform: scale(0.9);
    }
    100% {
        transform: scale(1);
    }
}