Most terminal themes were built for code. When your screen is 80% tool output, reasoning blocks, and permission prompts, you're reading paragraphs — not syntax. The contrast relationships that matter are different: body text needs to hold up at 11–13px over a four-hour session, not just pop on a hero slide.
klein-blue ships four variations, each making a different call about one specific question: what do you do with the ansi:redBright slot?
Claude Code uses that slot for its claude-sand brand color — a warm amber that appears on certain UI elements. That's the fork in the road. Neutralize it so nothing competes with Klein blue, or accept it as a second hero and let the two colors coexist. The four variations are four answers:
- Klein Void Refined — balanced, sand neutralized, no strong brand color presence
- Klein Void Sand & Sea — accepts claude-sand as a second hero alongside IKB
- Klein Void Prot — fully APCA-verified; every accent role passes strict gates (body Lc >= 90, subtle >= 75, muted >= 45, accent >= 60)
- Klein Void Gallery — maximum void, one blue, everything else steps back
The IKB problem is real: pure International Klein Blue on a dark ground measures Lc -12 under APCA — effectively invisible as body text. The fix is a split across two ANSI slots. Pure IKB stays in ansi:blue for decorative borders and highlights. Readable permission-prompt text moves to ansi:blueBright, lifted to a Klein-family hue that actually passes body-size gates.
Ships as macOS Terminal.app .terminal profiles with CommitMono-Regular and IBM Plex Mono bundled to ~/Library/Fonts/. One prerequisite: Claude Code's /theme picker must be set to dark-ansi, otherwise Claude Code ignores the ANSI layer entirely and renders from its hardcoded RGB palette.
git clone https://github.com/robertnowell/klein-blue
cd klein-blue
bash install.sh
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