diff --git a/decisions/perception.md b/decisions/perception.md
index a50753e03..17973782d 100644
--- a/decisions/perception.md
+++ b/decisions/perception.md
@@ -273,13 +273,16 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 - **Raised by:** Ozzie (timing values + urgency split, adopted), Araminta (visual transition spec), Gestalt (longer values not adopted, but playtesting may adjust)
 - **Dissent:** Gestalt proposed 0.8-1.2s (longer, more contemplative). Lead chose Ozzie's shorter values as starting point.
 
-### D-061: Dialogue box — bottom screen, max 20% height, no portraits
+### D-061: Dialogue box — unified conversation log, bottom screen, max 20% height, no portraits
 - **Date:** 2026-02-13
-- **Decision:** Dialogue occupies the bottom of the screen, max 20% height, max-width (not percentage-based — exact value TBD). Layout: NPC speech top, player response options below, left-aligned. Max 3 response options visible. Locked options invisible ([D-062](content.md#d-062-invisible-locked-dialogue-options)). NO portraits — the NPC is on screen, a portrait is redundant. Monologue floats ABOVE the dialogue box on z-layer 7 — spatial separation allows monologue to contradict dialogue visually (character thinks one thing while NPC says another). Walk-away via WASD, dialogue fades over 300ms, no close button ([D-064](content.md#d-064-walk-away--three-phase-consequences)). Auto-pause in single-player when implant UI is open; overlay design for multiplayer readiness.
-- **Rationale:** Game world stays live above the dialogue box — player sees NPC body language while talking. Monologue above + dialogue below = the character can think one thing while saying another. Max 3 options + invisible locks = player never knows what they're missing. No portrait because the NPC IS on screen.
-- **Cross-reference:** Invisible locks ([D-062](content.md#d-062-invisible-locked-dialogue-options)), confrontation ([D-063](content.md#d-063-confrontation--same-box-different-weight)), walk-away ([D-064](content.md#d-064-walk-away--three-phase-consequences)), z-stack ([D-049](#d-049-z-level-rendering-stack-8-layers))
-- **Source:** Control & Interaction Workshop (2026-02-13)
-- **Raised by:** Stig (UI spec + no portraits), Lead (20% height constraint + max-width directive)
+- **Decision:** Dialogue occupies the bottom of the screen, max 20% height, max-width 640px ([D-076](#d-076-dialogue-box-max-width--640px-oq-29-resolution)). NO portraits — the NPC is on screen, a portrait is redundant. Monologue floats ABOVE the dialogue box on z-layer 7 — spatial separation allows monologue to contradict dialogue visually (character thinks one thing while NPC says another). Walk-away via WASD, dialogue fades over 300ms, no close button ([D-064](content.md#d-064-walk-away--three-phase-consequences)). Auto-pause in single-player when implant UI is open; overlay design for multiplayer readiness.
+- **Unified conversation log (Sprint 14, #535):** The dialogue box is a single chronological log — not separate panels for active vs passive dialogue. Player-NPC conversations and overheard NPC-NPC conversations ([D-078](#d-078-overheard-npc-conversation--passive-dialogue-panel-with-occlusion-filter)) flow into the same scrolling log. Each entry shows `Speaker → Target: text` with per-character name colours (hash-indexed from configurable palette in `data/dialogue-theme.yaml`). Player response options render below the log; max 3 visible. Locked options invisible ([D-062](content.md#d-062-invisible-locked-dialogue-options)).
+- **Entry lifecycle:** All entries share the same timeout (15s + 3s fade, configurable via theme YAML). Walk-away clears response options but preserves log entries — earned information is fair game. Panel auto-hides when all entries expire and no active conversation is in progress.
+- **Passive overheard lines:** Rendered at reduced opacity (0.9) per [D-078](#d-078-overheard-npc-conversation--passive-dialogue-panel-with-occlusion-filter). No response options for overheard content. Walk-away does not fire for passive-only display — the panel dismisses naturally when entries expire or the player walks out of earshot.
+- **Rationale:** Game world stays live above the dialogue box — player sees NPC body language while talking. Monologue above + dialogue below = the character can think one thing while saying another. Max 3 options + invisible locks = player never knows what they're missing. No portrait because the NPC IS on screen. A single unified log avoids a separate UI element for overheard content and makes the flow of conversation feel natural — active and passive dialogue interleave chronologically.
+- **Cross-reference:** Invisible locks ([D-062](content.md#d-062-invisible-locked-dialogue-options)), confrontation ([D-063](content.md#d-063-confrontation--same-box-different-weight)), walk-away ([D-064](content.md#d-064-walk-away--three-phase-consequences)), z-stack ([D-049](#d-049-z-level-rendering-stack-8-layers)), max-width ([D-076](#d-076-dialogue-box-max-width--640px-oq-29-resolution)), overheard NPC conversation ([D-078](#d-078-overheard-npc-conversation--passive-dialogue-panel-with-occlusion-filter))
+- **Source:** Control & Interaction Workshop (2026-02-13). Amended Sprint 14 (#535): unified log architecture.
+- **Raised by:** Stig (UI spec + no portraits), Lead (20% height constraint + max-width directive). Sprint 14 unified log: Stig (implementation).
 - **Dissent:** Stig initially proposed 25% height and 50% width centered. Lead constrained to 20% height and max-width.
 
 ### D-067: Recognition chime fires at onset of cognitive delay
@@ -397,4 +400,4 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 
 ---
 
-*32 decisions. Last updated: 2026-02-19 (D-078: overheard NPC conversation — passive dialogue panel with occlusion filter)*
+*32 decisions. Last updated: 2026-02-20 (D-061: amended with unified conversation log architecture from Sprint 14 #535)*