Dying seedling, second one to look this way

50/50 soil:perlite is plenty good enough drainage qualities.. that is not the problem. there is not enough info. if the soil is exta hot, could be part of the problem, if it is falling over but not stretching, you may just need to reduce light a bit more, then amp it back up as the plant matures. if it's soft and possibly slimy at base, that's definitely watering issue. what are you watering habits? you should irrigate entire substsrate then wait for top 1" to dry before re-irrigating. don't leave dry pockets after an irrigation. A little runoff is okay, but a lot is wasteful realtive to soil context. if you were doing that, it is not 'overwatering'. sometimes it's hard to water properly if a small plant is in a large pot. it may take 10+ days for it to need another irrigation, and that's going to result in a substrate that remains wet for a long period of time... a good dry/wet cycle avoids pathogens and pests as well as promoting deeper, healthier roots, vs superficial roots and higher risk of infection. in such a case, which is totally avoidable using right sized pots and a transplant later, you want to water a column wround the seedling but still ensure it gets wet all the way down to the bottom. probably a diameter a bit wider than the seedling's canopy. this will help reduce how long it stays overly wet... as it grows into it, you can saturate entire pot. there are lots of reason leaves curl down.. it's incredibly easy to rule out overwatering.

It is a watering issue for sure. Can tell by the droopy leaves. May need to add perlite or coco to future grows in same stuff. Roots like air as well. They are likely rotting off. Sorry.