Line break in the dates

Hi All,
When I check the appointment page from desktop/tablet it looks just fine.
But on mobile the dates on the date picker gets unnecessary linebreaks.
Like:
1 instead of 13
3

http://prnt.sc/qgry35

I use the following CSV settings so far:
/*strech calendar for the whole page */
#fbuilder .ui-datepicker-inline { max-width:none !important; }
/*calendar header/row color */
#fbuilder .ui-datepicker-header { background:#1b7275 ;color:#FFF; font-size:20px; text-shadow:none}
/*calendar dates, font-size */
#fbuilder .ui-datepicker-calendar .ui-state-default {font-size:20px;}
/*calnedar NO borders */
#fbuilder .ui-datepicker table, #fbuilder .ui-datepicker thead, #fbuilder .ui-datepicker tr, #fbuilder .ui-datepicker th, #fbuilder .ui-datepicker td {border: 1px;}
#fbuilder .ui-datepicker{box-shadow:none}
/*available slots */
#fbuilder .slots{background:#f6e7bd;box-shadow:none}
#fbuilder .slots div{border:1px}
#fbuilder .slots div a{background:#e9a32f;color:#f4dba1}

What should I change to get it stretched all across different resolutions but get it displayed correctly on mobile as well?
Thanks!

The page I need help with: [log in to see the link]