Help centering widget with CSS instead of padding please?

Hi, i found a widget that i wanted to use on my site. however when i placed into upfront it was aligned to the left of the page. so i used some padding to get it aligned to the center. though when tested on mobile devices its pushed off the screen. so instead of the padding could i please have some CSS help to get it aligned to the center?
This is the element - placed in widget - -
screenshot on desktop -
screenshot on mobile device - 1 of 2 - 2 of 2 -
current left padding set to 400px -

website using Luke + Sara Upfront

domain -
Support Access is open

Please dont post any brand related information/ screenshots or domain links as i have had issues with google caching this information and linking it to their google searches of my site ... very bad for brand... please use temporary image upload / tiny url / pastebin etc to mask this information.