Audience-aware lessons. The header Client/Pro toggle switches the entire track. Progress is stored in your browser only.
The header audience toggle (Buyer / Engineer) switches the track. You are currently on the BUYER track.
Mark each lesson done to update progress.
Each lesson links into a tool: practise in Verifier, Simulator, Installation, Safety or Maintenance.
Continue the engineering loop — sizing, audit, intelligence, diagnostics, solar/UPS, library.