Flight Instructor reported a near miss with a paraglider while descending towards the airport on a training flight. The paraglider was not seen due to dusk conditions and the flight maneuvered to provide separation.

Narrative

While descending inbound back to GMU from the northwest; my student and I realized we were dangerously close to someone paragliding around 3000 ft. MSL. It was very difficult to see them with the available light from the sun quickly dissipating. As soon as we actually had the paraglider operator in sight; we pushed our nose down and turned to the right to avoid them. We didn't make a large correction because it did not appear we were going to imminently collide. We were not aware of any active paraglider activities in the area and I'm not positive that they were ever aware of our position either.We did not ask ATC about the paraglider and continued inbound.We were actively clearing the area for maneuvers throughout the flight. We were cross-checking ADS-B in as well. Throughout the flight; we never saw any traffic during our maneuvering. The setting sun we believe played a factor in us not being able to see the paraglider sooner. After taking corrective action with pitch down and right bank; we continued flying away from the paraglider in to GMU. Earlier in the flight; we were descending from above 3000 ft. MSL and it's also possible we did not see the traffic because of their position on the horizon relative to ours in addition to dusk setting in. My student had worked a full shift before his flight; and while this was my first flight today as an instructor; I have been at the flight school for several hours before hand; however; both of us seemed to be more than fit and alert to perform the training flight. To prevent this in the future; we will reevaluate our fatigue levels before each flight and ensure we're looking very carefully for slower; small; less maneuverable traffic ahead of us in addition to the bigger; more obvious airplanes and other such traffic we more commonly see and scan for.