diff --git a/.claude/memory/journal.md b/.claude/memory/journal.md
index a2a4207..9068865 100644
--- a/.claude/memory/journal.md
+++ b/.claude/memory/journal.md
@@ -111,3 +111,6 @@ Done: copy-mode-vi table had stock C-h cursor-left, C-u halfpage-up, C-j copy, s
 
 ## 2026-10-06 (pm, 8) — tmux drag "syntax error" in claude panes
 Done: MouseDrag1Pane binding had `\"` inside '...' (literal since tmux 3.0); branch for mouse-tracking panes (claude fullscreen, vim mouse=a) failed to parse → "syntax error", no selection. Backslashes dropped, pitfall noted in conf. Deployed to ~/.config/tmux/tmux.conf + source-file, live binding verified (`forwarded-to-app`). Merged bugfix/tmux-drag-syntax-error → develop (2245247). Closes the "deployed conf stale" open item.
+
+## 2026-10-07 — tmux dim inactive panes
+Done: window-style / window-active-style added. Two traps: colour234 ≈ iTerm2 dark bg (#15191f) → invisible; `window-active-style bg=default` inherits window-style since tmux 3 → active pane dimmed too, terminal colours hardcoded instead (fg #dcdcdc, bg #15191f). Inactive settled at #353d48 / #a6acb6 after 3 live rounds. Light macOS theme would need the inverse. Merged feature/tmux-dim-inactive-panes → develop.
diff --git a/tmux.conf b/tmux.conf
index 6b76418..bcda2e9 100644
--- a/tmux.conf
+++ b/tmux.conf
@@ -280,6 +280,14 @@ set -g status-right '#{sep_b} #h #{sep_e}#{sep_on} : #{continuum_status} '
 set -g pane-active-border-style fg=white,bg=white
 set -g pane-border-style fg=white,bg=default
 
+# Dim inactive panes: only cells in "default" colour change (coloured text and
+# vim's own background stay as they are). The active style must repeat the
+# terminal colours: since tmux 3, "default" there inherits window-style, so
+# the active pane would be dimmed too. Values = iTerm2 Default profile, dark
+# mode (fg #dcdcdc, bg #15191f); a light theme needs the opposite.
+set -g window-style        fg=#a6acb6,bg=#353d48
+set -g window-active-style fg=#dcdcdc,bg=#15191f
+
 # set Message text
 set-option -g message-style bg=default,fg=red
 set-option -g message-command-style bg=default,fg=brightwhite