If you're scouting for a casual but also stylish look, wear a long sleeve shirt with navy sweatpants. Here's how to play it up: dark brown leather desert boots.
Navy Sweatpants with Long Sleeve Shirt Smart Casual Outfits For Men
For an ensemble that's very simple but can be modified in a ton of different ways, team a long sleeve shirt with navy sweatpants. White leather low top sneakers will tie the whole thing together.