Is Cocktail Attire an OK choice for this wedding?

Planning a very small wedding and trying to determine if Cocktail Attire would be an OK choice for this time/venue.

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It is indoors in a small lounge/event center. There is not a meal, instead an array of refreshments, a dessert bar, cocktails/mocktails, and other beverages at the bar. The entire ceremony/reception is from 1pm-4pm.