Combini de Kimi to no 5-funkan. - Vol. 1 Ch. 14

[MangaDex]

 

[andrybak]

quote from Wiktionary for スマート:

スマート • (sumāto)

1. slim, trim, slender
2. stylish

Japanese borrowed words can sometimes take on weird meanings (like "style" to mean "body", "physique"), but this one is basically an extension of the other meaning of "smart" in English