Keep in mind this is a loft bed. As such the access should be compared to climbing a ladder, which is how one typically climbs up to a loft bed. This is not to a stair accessing a mezzanine space, which obviously would need a different type of stair.

It should be noted that the stair was originally designed with handrails; however, when it was mocked up in the shop it became obvious that handrails would have been superfluous. It's very hard to imagine this without physically trying it, but everyone who has climbed this stair intuitively holds the sides of the risers (the vertical parts of the stair) and climbs the stair similarly to climbing a ladder. All who have tried it agree that it is a much more comfortable and secure than a typical loft bed ladder.

Amazing design. Does it feel unsafe when climbing down?

Also what are the suggested tread and riser measurements pls?

Fun!