.period-past {
    background-color: #f0f0f0;
}

.period-current {
    background: repeating-linear-gradient(
        45deg,
        #f0f0f0,
        #f0f0f0 10px,
        #ffffff 10px,
        #ffffff 20px
    );
}

.period-future {
    background-color: #ffffff;
}