Classic pajama pant set in end-on-end cotton

The very first set of "matching" pajamas I bought for myself in high school... after the graphic tee/boxer short trend sweeping the all-girls' boarding schools of the Eastern Seaboard passed. I still have that pair but they're finally getting a little threadbare. I have a big pajama collection because I like to wear a fresh set every night and feel coordinated. The navy with white piping is a classic.