hosteren/EMDR-for-browsers ? reverse-engineered prompt

Build me a simple web page for doing EMDR at home.

I want a clean, calming screen with a black dot that moves back and forth so I can follow it with my eyes, and it should blink or animate in a way that feels easy to track. Add alternating beeps that match the movement, and let me change the speed or timing with a slider so I can make it slower or faster depending on what feels comfortable.

Keep it very simple and accessible, with clear controls and a minimal design so there are no distractions. It should work in a browser without any setup, and if you need to look up current best practices for audio playback or browser compatibility, go ahead and do that.

Please also include a short usage note on the page that explains how someone would use it, plus a gentle disclaimer that it is not a replacement for professional therapy.