Smart casual is the most misread dress code there is. It is not "anything goes" - it is relaxed pieces worn with clear intent.
Polished but not formal: one step up from what you would wear on a weekend, one step down from a full suit. Think elevated basics that fit well.
Include one refined element (a blazer, a leather shoe, a crisp shirt); choose fit over flash; and keep a neutral base with a single accent. Hit those three and you are there.
Avoid both extremes - full sportswear or a stiff business suit. Clean minimal sneakers can work; gym sneakers cannot. A plain tee can work; a loud graphic tee usually cannot.
Ask Stirolo what to wear for any occasion and it assembles smart-casual looks from pieces you already own.