lightsout.css

#lightsout * {
    box-sizing: border-box;
}

#lightsout {
    width: 10em;
    margin: auto;
}

#lightsout-timer {
    width: 3em;

    font-size: 2em;
    text-align: center;

    margin: auto;
}

#lightsout-board {
    font-size: 2em;

    width: 5em;
    height: 5em;

    display: grid;
    grid-template-columns: repeat(5, 1em);

    background-color: rgb(90, 90, 90);

    margin: auto;
    margin-bottom: 20px;
    border: 1px solid black;
}

.lightsout-square {
    width: 1em;
    height: 1em;

    grid-row-start: auto;
    grid-column-start: auto;


    border: 1px solid black;
}

.js-lightsout-square-on {
    background-color: white;
}

#lightsout-newgame-btn {
    display: block;

    margin: auto;
    margin-bottom: 20px;
    padding-top: 0.3em;
}




#overlay {
    position:absolute;
    top:0;
    left:0;
    width:100%;
    height:100%;
    z-index:1000;
    background-color: rgba(0, 0, 0, 0.5);
    opacity:0;
    display:none;
}
#container {
    position:absolute;
    top:30%;
    left:50%;
    margin-left:-200px;
    width: 400px;
    height:250px;
    background-color:#111;
    padding:5px;
    border-radius:4px;
    color:#FFF;
}