Yes you can go casual...business casual was the norm for most people, i went in shorts and nice T-Shirt
We wear dinner attire when we go, but have seen people in dress casual.
Wear what you feel comfortable wearing. It is a nice place though.
I have seen any attire from formal wear for prom to casual dress.
I went in jeans and a polo. I saw people in suits and dresses and others in t-shirts. But most people were dressed up to some extent.
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