body {
    display: grid;
    grid:
        "header" minmax(82px, auto) "main" minmax(100px, auto) "footer" 50px / 1fr;
    min-height: 100vh;
}

#main-header {
    grid-area: header;
    text-align: center;
}

#main-header button {
    border: 0;
    font-size: 16px;
    margin: 2px;
    padding: 10px 5px;
}

main {
    display: grid;
    align-items: center;
    grid-area: main;
    justify-items: center;
}

#main-footer {
    grid-area: footer;
}

.border {
    border: 1px solid #000;
}

#close {
    border: 0;
    font-size: 16px;
    margin: 2px 0;
    padding: 10px 5px;
    width: 100%;
}