body {
    text-align: center;
    font-family: Arial, Helvetica, sans-serif;
    font-size: 16px;
}
#people, #salary, #worktime {
    width: 80px;
    text-align: right;
}
#timerText {
    color: blue;
    font-size: 32px;
}
#timeText, #costText {
    color: red;
    font-size: 32px;
}
.btn {
    display: inline-block;
    width: 90px;
    padding: 6px;
    border-radius: 5px;
    box-shadow: 0 4px 0 #3a00cc;
    color: #fff;
    background: #7b00ee;
    cursor: pointer;
}
.btn + .btn {
    margin-left: 5px;
}
.btn.active {
    opacity: 1.0;
}
.btn.inactive {
    opacity: 0.5;
}