div.tabs {
    display: flex;
    flex-direction: row;
}

div.tabs>div {
    border: 1px black solid;
    margin: 0px 3px 0px 0px; /* Top, Right, Bottom & Left */
}

div.tab {
    border: 1px black solid;
    padding: 3px 3px 3px 3px;
}

.flex-row {
    width: 100%;
    display: flex;
    flex-direction: row;
}

div#calc {
    width: 30%;
    display: flex;
    flex-direction: column;
    justify-content: right;
    align-items: flex-end;
    align-content: flex-end;
}

div#calc input[type=number] {
    width: 60%;
}