* {
    border: 4px solid black;
    border-radius: 8px;
    margin: 4px;
}

html, body {
    border: none;
    margin: 0;
}

body {
    display: flex;
    align-content: center;
    text-align: center;
    font-family: monospace;
    font-size: 20px;
    justify-content: center;
}

.container {
    margin-top: 100px;
    width: 400px;
    height: 400px;
    align-content: center;
}

.item {
    align-content: center;
    justify-content: center;
    width: 100px;
    height: 100px;
}

#flex {
    display: flex;
}

#grid {
    display: grid;
    grid-template-rows: 133px 133px 133px;
    grid-template-columns: 133px 133px 133px;
}