.booking-widget .cal-mon-table .no-avail-start {
    background: linear-gradient(to bottom right, #fff 0%, #fff 50%, #ddd 50%, #ddd 100%);
}
.booking-widget .cal-mon-table .no-avail-end {
    background: linear-gradient(to bottom right, #ddd 0%, #ddd 50%, #fff 50%, #fff 100%);
}

.booking-widget .cal-mon-table .highlight-start {
    background: linear-gradient(to bottom right, #fff 0%, #fff 50%, orange 50%, orange 100%);
}
.booking-widget .cal-mon-table .highlight-end {
    background: linear-gradient(to bottom right, orange 0%, orange 50%, #fff 50%, #fff 100%);
}
.booking-widget .cal-mon-table .highlight-end.no-avail { 
    background: linear-gradient(to bottom right, orange 0%, orange 50%, #ddd 50%, #ddd 100%); 
}
.booking-widget .cal-mon-table .highlight-start.no-avail-end {
    background: linear-gradient(to bottom right, #ddd 0%, #ddd 50%, orange 50%, orange 100%);
}