* { margin:0;
    /* box-sizing: border-box;   */
    /* border and padding will be included in elements */
}
body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    margin:0; padding:0; 
}
.container{position: relative;}

.content {position:absolute; z-index: 100;}
input, button {margin-bottom: .4rem;}
#countdown {
    width: 4rem;
    height: 4rem;
    text-align: center;
}
.check-button {
  
}

canvas {
    position:absolute; z-index: 10;
    background-color:rgb(0, 5, 12);  
}