According to Chinese traffic safety guidelines and GB 811-2022, what is the regulation regarding the use of dark tinted or mirrored helmet visors at night or inside unlit tunnels?

1. They are mandatory at night to prevent glare from oncoming high-beam headlights
2. They may be used at night provided the rider increases vehicle speed to sharpen optical contrast
3. They are strictly prohibited because they excessively reduce visible light transmission below legal thresholds, severely impairing night vision
4. They are permitted at night only if the motorcycle is equipped with auxiliary off-road LED spotlights