Handmade recliner workstation

I am concerned about the health of my son because he spends a lot of time playing computer games.I want to make for him a workstation with adjustable tilt of the chair and monitor as in Altwork Station or Human Touch Zero Gravity Chair, but without  complicated electric mechanisms. Unfortunately the price of such things in Ukraine is incredibly expensive, so I want to do it myself. Can someone help with ideas or plans ? Tnx
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