diff --git a/troubleshooting.md b/troubleshooting.md
index 68d51f3..9a746f1 100644
--- a/troubleshooting.md
+++ b/troubleshooting.md
@@ -73,7 +73,60 @@ Synaptics scroll direction options:
 
 # Theme switching issues
 
-## Tmux and terminal not updating after theme switch
+## Cross-application theme synchronization
+
+**Issue:** Need to synchronize theme (light/dark) across tmux, nvim, and other terminal applications.
+
+**Solution:** File-based theme management system using `~/.vim_theme`:
+
+### Setup:
+
+1. **Create theme switcher script** (`~/.config/tmux/themeswitch.sh`):
+```bash
+#!/bin/bash
+if [ -f ~/.vim_theme ] && [ "$(cat ~/.vim_theme)" = "light" ]; then
+    tmux set -g @catppuccin_flavor "latte"
+else
+    tmux set -g @catppuccin_flavor "mocha"
+fi
+```
+
+2. **Add to tmux config** (`~/.config/tmux/tmux.conf`):
+```bash
+# Dynamic theme switching based on ~/.vim_theme file
+run 'bash ~/.config/tmux/themeswitch.sh'
+```
+
+3. **Add to shell config** (`~/.zshrc`):
+```bash
+# Export THEME environment variable for nvim and other apps
+if [ -f ~/.vim_theme ]; then
+    export THEME=$(cat ~/.vim_theme)
+else
+    export THEME="dark"  # default
+fi
+```
+
+### Usage:
+```bash
+# Switch to light theme
+echo "light" > ~/.vim_theme
+
+# Switch to dark theme
+echo "dark" > ~/.vim_theme
+```
+
+### Benefits:
+- ✅ **Single source of truth:** `~/.vim_theme` file controls all applications
+- ✅ **Automatic propagation:** New terminals inherit theme via shell config
+- ✅ **No environment variable issues:** File-based approach avoids tmux env var propagation problems
+- ✅ **Cross-application support:** nvim reads `$THEME`, tmux uses catppuccin flavors
+
+### Limitations:
+- **Tmux live reload:** Changes require tmux config reload or session restart
+- **Workaround:** Use tmux-resurrect to quickly restore sessions after restart
+
+## Legacy: Tmux and terminal not updating after theme switch
 
 **Issue:** After running the theme switcher script, tmux sessions and existing terminals don't reflect the new theme until restarted.
 
@@ -81,10 +134,7 @@ Synaptics scroll direction options:
 - Restart tmux sessions: `tmux kill-server && tmux`
 - Open new terminal windows
 
-**TODO:**
-- Investigate tmux theme reload without killing sessions
-- Check if terminal emulator supports theme change signals
-- Improve theme script to handle live theme updates
+**Status:** ✅ **Solved** - Use file-based theme management system above
 
 ## Tmux window names showing hostname instead of command
 
@@ -201,3 +251,20 @@ sudo setkeycodes 3a 14  # Map caps lock scancode to backspace keycode
 ```
 
 **Permanent fix:** Systemd service created at `/etc/systemd/system/caps-backspace.service`
+
+## Laptop sleeps when lid is closed
+
+Solution:
+
+sudo nvim /etc/systemd/logind.conf
+
+Uncomment and change these lines:
+
+```
+HandleLidSwitch=ignore
+HandleLidSwitchExternalPower=ignore
+HandleLidSwitchDocked=ignore
+```
+
+Then restart service:
+`sudo systemctl restart systemd-logind`