Have you ever paused mid-downward dog and wondered what's actually beneath your hands and feet? What materials make up that trusty mat you roll out every morning? And more importantly, what happens to it once it's worn out and headed for the bin?   These questions might seem small, but they carry significant weight for anyone trying to live more sustainably. Your yoga mat is more than just a cushion between you and the floor—it's a product you breathe near, sweat on, and use