diff --git a/decisions/0001-paleta-complementaria.md b/decisions/0001-paleta-complementaria.md
new file mode 100644
index 0000000..fad69d6
--- /dev/null
+++ b/decisions/0001-paleta-complementaria.md
@@ -0,0 +1,53 @@
+# ADR-0001 · Complementary palette over classic LCARS
+
+**Status**: accepted
+**Date**: 2026-05
+**Decision-makers**: design + product
+
+## Context
+
+Early UI sketches used classic LCARS palette (orange/peach/yellow on black). The aesthetic worked for demonstrating the visual language but had two practical problems:
+
+1. **Brand collision** — Blocao's logo and brand mark are lime green (`#9FCB3A`). Orange-dominant LCARS placed the brand in the same warm-color family, diluting it visually.
+2. **Domain semantics** — orange traditionally means "warning" in industrial UI. Using orange as the dominant neutral color made every screen feel mildly alarming and made it impossible to use orange for actual warnings.
+
+## Decision
+
+Adopt a **complementary palette** rotated ~180° from classic LCARS. Cyan-dominant instead of orange-dominant.
+
+Token palette (final):
+
+```
+--ink:    #66CCFF   /* primary navigation, dominant */
+--cam:    #6699FF   /* cameras / VLAN-10 */
+--hai:    #CC99CC   /* compute / VLAN-20 (mauve) */
+--iot:    #99CC99   /* health / OK states (green) */
+--mgmt:   #CCCC99   /* management / VLAN-30 (olive) */
+--wan:    #66CCCC   /* WAN / external (turquoise) */
+--warn:   #99FFFF   /* warnings (bright cyan) */
+--brand:  #9FCB3A   /* Blocao green — logo and brand only */
+```
+
+The brand green is **isolated** from semantic UI. It only appears for logo, brand chip in the status strip, and explicit brand moments. UI states never reuse brand color.
+
+## Consequences
+
+**Good**:
+- Brand green stands out against cyan-dominant chrome.
+- Warnings can use bright cyan (`--warn`) which contrasts against the cyan-blue chrome without being confused with normal text.
+- The palette feels distinctive without losing LCARS character.
+
+**Bad / trade-offs**:
+- Less immediately recognizable as "LCARS" to Star Trek fans.
+- Some viewers in the early demos commented "feels like a different visual language" — that's actually intended but worth noting.
+
+## Alternatives considered
+
+- **Pure classic LCARS**: rejected for reasons above.
+- **Custom palette unrelated to LCARS**: would lose the visual hook that makes Blocao memorable.
+- **Brand-color-as-dominant** (lime green everywhere): too aggressive, reduces accessibility on dark backgrounds, exhausts the eye.
+
+## See also
+
+- `mockups/palette-comparison.html` — interactive toggle between classic and complementary.
+- `docs/03-design/design-tokens.md` — the full token table.