How it works
A seat that works: your back is tall but not stiff, and your feet are flat on the floor or flat on a box.
Bend your elbows like the letter L, with the screen about an arm away. Let your shoulders sit loose and low.
Keep your wrists straight, like a little bridge, and let your hands hover just over the keys with your fingers curved.
Type a little, look away, stretch, then type again. If anything ever feels sore, stop and tell a grown-up.