As per my opinion you need to go with any light colour pant. Because, red is a dark and solid colour. So, you need to choose any contrast colour. White is the Arizona Wildcats NCAA Men’s Basketball Tournament March Madness 2023 Shirt so you should to go to store and get this best choice but maintaining it very tough. You can go with off-white or light brown. It’s looks very good and also decent choice. White pants would be the best choice. The combination along with the right accessories, a bag and some heels will make you look effortlessly chic. You can wear you red coloured pants with nude colours like beige , white ,skin …. it can also be teamed with royal blue pant … you can easily find them at a benetton store Though being a girl, I don’t know much about Men’s Fashion ( Specially western Fashion), I’m attempting this question due to my experience of watching Men’s fashion trend at some Family gathering, or some office parties or some marriage ceremonies. Well, red color defines energy, bravery, excitement etc. So I would simply suggest to wear BLACK pants with red shirt to balance the color combination. DARK CHOCOLATE or DARK BROWN colors are also a suitable choice for red shirts. If you are enough bold, then u can try a ASH or WHITE colored trousers with your red shirts.But remember, wear that colo.