style.css

body, html {
    height: 100%;
    overflow-y: hidden;
}

#loading {
    position: absolute;
    text-align: center;
    padding-top: 49vh;
    height: 100%;
    width: 100%;
    background-color: white;
    font-size: larger;
}

#app {
    display: flex;
    flex-direction: column;
    justify-content: center;
    height: 100%;
}

#board {
    display: flex;
    flex-direction: column;
    height: 90vw;
    width: 90%;
    margin: 0 auto;
    background-color: rgba(255, 160, 122, 0.288);
}

#board > .row {
    display: flex;
    height: 100%;
}

#board > .row > .cell {
    width: 100%;
    height: 100%;
    font-size: 32px;
    font-family: monospace;
    text-align: center;
    border:solid;
    border-width: 1px;
}

.input-control {
    display: flex;
    justify-content: center;
    margin-bottom: 10px;
}

.wraper-move {
    margin-top: 10px;
    text-align: center;
    font-size: xx-large;
}

.wraper-move > a {
    margin: 10px;
    color:lightsalmon;
}

a[disabled] {
    pointer-events: none;
    cursor: default;
    color:gray;
}

#ai-timing {
    text-align: center;
}

.invisible {
    display: none;
}

@media only screen and (min-width: 768px) {
    #board {
        height: 450px;
        width: 450px;
    }

    #app {
        justify-content: initial;
        margin-top: 50px;
    }
}