Is this too much water, too little water, too much light, too little light, or somthing else entirely?

Please help!

Thank you!

Light should have nothing to do with it. Seedlings need light (about 16 hours a day) and also some darkness. With little light they will just not grow, they should not turn yellow because of this. I would hold back on the watering and let the soil dry out a bit. A good test for watering is to stick your pinky in about 1/2 inch and if its wet then hold off but if not give it a good drink.

My own take is that yellow means too much water and temps too cold, followed maybe by too little nutes?