styles.css

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
}

.grid {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.row1, .row2, .row3 {
    display: flex;
}

.box {
    width: 100px;
    height: 100px;
    border: 1px solid #000;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2em;
    cursor: pointer;
    background-color: #ffffff;
    color: #fff;
}

.row1 .box {
    border-top: none;
}

.row3 .box {
    border-bottom: none;
}

.row1 .box:first-child,
.row2 .box:first-child,
.row3 .box:first-child {
    border-left: none;
}

.row1 .box:last-child,
.row2 .box:last-child,
.row3 .box:last-child {
    border-right: none;
}

.box:hover {
    background-color: #e0e0e0;
}

#X {
    display: none;
}

#O {
    display: none;
}

#tie {
    display: none;
}