feat(wezterm): dim unfocused windows

README.md

@@ -20,7 +20,7 @@ Running the switch builds:
 - Nix user packages (ripgrep, fd, fzf, jq, lazygit, Neovim, Hack Nerd Font)
 - Shell (zsh, aliases, starship prompt)
 - Editor (Neovim config with the rose-pine moon theme)
-- Terminal (WezTerm config with the rose-pine moon theme)
+- Terminal (WezTerm config with the rose-pine moon theme and dimmed unfocused windows)
 - Agent configs (Claude, Codex, opencode all share one AGENTS.md)
 
 ## Prerequisites

home/.config/wezterm/wezterm.lua

@@ -10,4 +10,38 @@ config.macos_window_background_blur = 50
 config.hide_tab_bar_if_only_one_tab = true
 config.window_decorations = "RESIZE"
 
+-- Dim unfocused windows so the focused one is obvious at a glance.
+local UNFOCUSED_FOREGROUND_TEXT_HSB = { hue = 1.0, saturation = 0.25, brightness = 0.45 }
+local UNFOCUSED_WINDOW_BACKGROUND_OPACITY = 0.62
+
+-- get_config_overrides() hands back a copy, so the current value is never the
+-- same table we last stored; compare the fields instead of the identity.
+local function same_text_hsb(actual, expected)
+	if actual == nil or expected == nil then
+		return actual == expected
+	end
+	return actual.hue == expected.hue
+		and actual.saturation == expected.saturation
+		and actual.brightness == expected.brightness
+end
+
+wezterm.on("window-focus-changed", function(window)
+	local overrides = window:get_config_overrides() or {}
+	local text_hsb, opacity
+	if not window:is_focused() then
+		text_hsb = UNFOCUSED_FOREGROUND_TEXT_HSB
+		opacity = UNFOCUSED_WINDOW_BACKGROUND_OPACITY
+	end
+
+	-- Only write when one of the two values we own actually changes; a redundant
+	-- set_config_overrides() call would trigger another config reload.
+	if same_text_hsb(overrides.foreground_text_hsb, text_hsb) and overrides.window_background_opacity == opacity then
+		return
+	end
+
+	overrides.foreground_text_hsb = text_hsb
+	overrides.window_background_opacity = opacity
+	window:set_config_overrides(overrides)
+end)
+
 return config