* {
    margin: 0;
    padding: 0;
}

.App {
    display: flex;
    flex-direction: column;
    align-items: center;

    min-width: 100vw;
    min-height: 100vh;
    width: 100%;
    height: 100%;

    background-color: gray;
}

.Viewport {
    font-size: 32px;

    width: 10em;
    height: 10em;

    margin-top: 1em;

    position: relative;

    background-color: darkgray;
    background-image: repeating-linear-gradient(black 0, transparent 1px, transparent calc(1em - 1px), black 1em),
    repeating-linear-gradient(90deg, black 0, transparent 1px, transparent calc(1em - 1px), black 1em);
}

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

    width: calc(1em - 2px);
    height: calc(1em - 2px);

    position: absolute;

    background-color: lightgray;
    border: 1px solid black;

    user-select: none;
}

.Token.selected {
    z-index: 1;
    border-color: lightgreen;
}