diff --git a/sway/.config/sway/config b/sway/.config/sway/config
index 87eb334..c787676 100644
--- a/sway/.config/sway/config
+++ b/sway/.config/sway/config
@@ -4,6 +4,8 @@ exec_always ~/.config/sway/scripts/workspace-colors.py
 exec_always eww daemon && (eww open bar0 || true) && (eww open bar1 || true)
 exec_always mako
 
+exec /usr/libexec/polkit-mate-authentication-agent-1
+
 exec swayidle -w \
       timeout 900 '~/.local/bin/smart-dim.sh' \
       resume 'brightnessctl -r'
@@ -143,6 +145,9 @@ mode "resize" {
 }
 bindsym $mod+r mode "resize"
 #
+# Toggle dark/light theme
+bindsym $mod+y exec ~/.config/sway/scripts/toggle-theme.sh
+
 # Utilities:
 #
     # Special keys to adjust volume via PulseAudio
diff --git a/sway/.config/sway/scripts/toggle-theme.sh b/sway/.config/sway/scripts/toggle-theme.sh
new file mode 100755
index 0000000..7d9ee5d
--- /dev/null
+++ b/sway/.config/sway/scripts/toggle-theme.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+# Toggle between dark and light themes for wezterm and nvim
+# Source of truth: ~/.config/theme-state
+
+STATE_FILE="$HOME/.config/theme-state"
+
+# Read current state
+current="dark"
+if [ -f "$STATE_FILE" ]; then
+  current=$(cat "$STATE_FILE" | tr -d '[:space:]')
+fi
+
+# Toggle
+if [ "$current" = "light" ]; then
+  next="dark"
+else
+  next="light"
+fi
+
+# Write new state
+# - wezterm watches this file via add_to_config_reload_watch_list and auto-reloads
+# - nvim watches this file via vim.uv.fs_event and auto-switches colorscheme
+echo "$next" > "$STATE_FILE"