The principle
Cobalt is the most protected color in the system. When it starts being used as a link color or as a highlight, the customer loses the only reliable cue for knowing they are reading a machine. Green, red, and amber appear by meaning: green for done, connected, and healthy; red for real danger, such as deleting, logging out, validation errors, and a channel that is down; amber for a pending state that is not yet an error. Using red as a highlight spends the only word the system has for saying danger. SAN blue, #007BFF, stays out of the product interface: it collides with cobalt. Its place is the provenance seal.Ratio
The screen is almost entirely neutral: about 60% paper, 25% ink, with the rest split between the two signals. A screen that is mostly terracotta or mostly cobalt is wrong even if it uses the right colors.
Palette
Base
Paper and ink carry about 85% of any screen.
Signals
Terracotta is the people’s side, cobalt is the AI’s side; the highlight is for when there is no encounter.
States
They appear by meaning, each with a background veil and a text tone.
Dark theme
The signals lighten to keep contrast against ink; never reuse the light-theme tone.