html, body {
    height: 100%;
    width: 100%;
    margin: 0%;
}

#container {
    position: absolute;
    height: 100%;
    width: 100%;
    margin: 0%;
}

#dialog {
    /*visibility: hidden;*/
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    margin-top: 50px;
    width: 100%;
    height: 100%;
    z-index: 999;
    text-align: center;
    /*display: flex;
    justify-content: center;
    align-items: center;*/
}

#menu {
    box-sizing: border-box;
    float: none;
    margin-left: auto;
    margin-right: auto;
    margin-top: 100px;
    margin-bottom: auto;
    /*width: 75%;*/
    width: 310px;
    /*height: 33.3%;*/
    height: 200px;
    text-align: center;
    border: 3px solid black;
}

#title {
    position: relative;
    margin-top: 5%;
    font-size: 50px;
    font-family: cursive;
}

#author {
    position: relative;
    margin-top: 0%;
    margin-bottom: 5%;
    font-size: 20px;
    font-family: cursive;
}

/*#startGame {
    position: relative;
    margin-top: 5%;
}*/

#1Player, #2Player {
    position: relative;
    margin-top: 0%;
}

#board {
    display: none;
    margin-left: 2.5%;
    margin-right: auto;
    margin-top: 15px;
    margin-bottom: auto;
    width: 95%;
    height: 95%;
    border: 1px solid black;
}

.cell {
    box-sizing: border-box;
    float: left;
    margin-left: auto;
    margin-right: auto;
    margin-top: auto;
    margin-bottom: auto;
    width: 33.3%;
    height: 33.3%;
    display: flex;
    justify-content: center;
    align-items: center;
}

#x1y1 {
    border-right: 3px solid black;
    border-bottom: 3px solid black;
    
}

#x2y1 {
    border-right: 3px solid black;
    border-left: 3px solid black;
    border-bottom: 3px solid black;
}

#x3y1 {
    border-left: 3px solid black;
    border-bottom: 3px solid black;
}

#x1y2 {
    border-right: 3px solid black;
    border-top: 3px solid black;
    border-bottom: 3px solid black;
}

#x2y2 {
    border-right: 3px solid black;
    border-left: 3px solid black;
    border-top: 3px solid black;
    border-bottom: 3px solid black;
}

#x3y2 {
    border-left: 3px solid black;
    border-top: 3px solid black;
    border-bottom: 3px solid black;
}

#x1y3 {
    border-right: 3px solid black;
    border-top: 3px solid black;
}

#x2y3 {
    border-right: 3px solid black;
    border-left: 3px solid black;
    border-top: 3px solid black;
}

#x3y3 {
    border-left: 3px solid black;
    border-top: 3px solid black;
}