Heat-Stress Psychrometric Map

This is the 2D counterpart of the Human Thermoregulation in a Heatwave simulator: the same one-node core-temperature heat balance and psychrometric evaporation limit, rendered as a live field map of the whole temperature/humidity plane instead of a 3D body. A heatmap shows evaporative cooling capacity everywhere on that plane and tracks your current slider position with a marker; a strip chart plays out core temperature over exposure time; a 2D skin cross-section shows sweat droplets either flash-evaporating (cooling) or sliding uselessly down the skin (not cooling) depending on whether the surrounding air can actually absorb the moisture. The key insight is the same one made visible from a different angle: evaporative cooling is capped by how much moisture the air can absorb, not by how hard the body sweats, so in humid heat sweat keeps flowing while core temperature keeps climbing anyway.