Can I get smaller sidebar widget date icons?

I’m trying to use the time.ly app as a sidebar widget to list upcoming events. My trouble is that I only have one event per day, each event only takes up one line, and the date badge/icon is too large. It seems like it’d be great if I had several lines in my event title or several events in the date, but as it stands, it’s taking up way too much space. I’m working with the Highend theme. I would like to know if there’s a way to make those icons smaller, so that they only take up one line. Or if there are options to change to different icons that are, themselves, smaller.

Note: This website is for my business. I am not a professional developer, so all suggestions must be explained to me like I am a moron. “Add this to your CSS” will baffle me unless you tell me exactly where to find that and exactly where to put that. Compared to your abilities, I’m that kindergartener sitting in the corner eating paste.

https://www.ads-software.com/plugins/all-in-one-event-calendar/