.chessboard {
    width: 640px;
    height: 640px;
    border: 25px solid #333;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    cursor: default;
}

.background {
    background-color: red; /* for visualization purposes */
    display: inline-block;
}

.black, .white, .black_, .white_ {
    float: left;
    width: 80px;
    height: 80px;
    font-size: 50px;
    
    text-align: center;
    display: table-cell;
    vertical-align: middle;

}
.black, .black_ {
    background-color: #999;

}

.white, .white_ {
    background-color: #fff;
}

.white_, .black_ {
	border: 2px solid red;
    cursor: pointer;
	box-sizing: border-box;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
}

.skip-chess-btn {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: white;
    border: 2px solid #333;
    color: #333;
    padding: 8px 16px;
    font-family: monospace;
    font-size: 14px;
    font-weight: bold;
    cursor: pointer;
    box-shadow: 2px 2px 0px #999;
    transition: all 0.1s ease;
}

.skip-chess-btn:hover {
    background-color: #f0f0f0;
    transform: translateY(1px);
    box-shadow: 1px 1px 0px #999;
}

.skip-chess-btn:active {
    background-color: #333;
    color: white;
    transform: translateY(2px);
    box-shadow: none;
}

#message {
    padding-top: 5px;
    font-size: 30px;
}