Looking for 1st birthday party theme ideas!

My daughter was born on New Year's eve last year, and her first birthday perfectly falls on a Saturday.  We don't have a lot of space at our house, so we are going swimming at a hotel in town. They have a poolside room that they use for birthday parties. I am in MN, so it will be cold and snowy. What is a good party theme that I should do? I am horrible with these things! I remember seeing posts of cute ideas people did, but I can't remember any of them. Any ideas and suggestions are much appreciated! Thank you 🙂