h1, h3{
    text-align: center;
}



/* pokus */


:root {
    --grid-cols: 1;
    --grid-rows: 1;
}

#container {
    margin: auto;
    width: 850px;
    height: 850px;
    display: grid;
    grid-template-rows: repeat(var(--grid-rows), 1fr);
    grid-template-columns: repeat(var(--grid-cols), 1fr);
}

.grid-item {
    border: 1px solid #ddd;
    text-align: center;
    width: 30px;
    height: 30px;
}

#container_layout{
    display: flex;
}