Definitive proof that a navy crew-neck t-shirt and grey sweatpants look amazing when paired together in a casual street style getup. And if you want to effortlessly perk up this look with a pair of shoes, complement this ensemble with a pair of beige canvas low top sneakers. Clearly, you're looking at a great choice for a super hot day. Those who are curious how to wear cool casual looks as you make your way through your 20s, this combination should answer your question.