diff --git a/dot_claude/rules/development-principles.md b/dot_claude/rules/development-principles.md
new file mode 100644
index 0000000..b4683de
--- /dev/null
+++ b/dot_claude/rules/development-principles.md
@@ -0,0 +1,34 @@
+---
+alwaysApply: true
+---
+
+# Development Principles
+
+## Test-Driven Development
+
+- Write tests first, then implementation
+- Red → Green → Refactor cycle
+
+## Simplicity
+
+- Less code is better code
+- Do not add lines without explicit user request
+- Avoid over-engineering and premature abstraction
+
+## Modern Practices
+
+- Use latest language features and idioms
+- Prefer modern libraries over legacy alternatives
+- Stay current with ecosystem best practices
+
+## Honesty
+
+- Do not answer questions with actions
+- Do not speculate on specifications — ask or investigate
+- Admit uncertainty rather than guessing
+
+## Comments
+
+- Write "why", not "what"
+- Only add "what" comments when improving multi-line code readability
+- Avoid redundant comments that restate obvious code
diff --git a/dot_tmux.conf b/dot_tmux.conf
index 7893e49..089571a 100644
--- a/dot_tmux.conf
+++ b/dot_tmux.conf
@@ -104,14 +104,14 @@ bind u run-shell -b "tmux capture-pane -pS -5000 | grep -oE 'https?://[^[:space:
 # key, otherwise C-a still gets captured by the outer tmux.
 
 # F12 in root table switches to "off" mode (disable prefix + switch key-table)
-# Visual: subtle dark background with muted pink indicator
+# Visual: muted background with pink indicator
 # Also disable mouse so events pass through to inner tmux
 bind -T root F12 \
   set prefix None \; \
   set key-table off \; \
   set -g mouse off \; \
-  set status-style "bg=#313244,fg=#6c7086" \; \
-  set status-left "#[bg=#eba0ac,fg=#1e1e2e,bold] 🔓 PASSTHROUGH #[bg=#313244] " \; \
+  set status-style "bg=#33467c,fg=#565f89" \; \
+  set status-left "#[bg=#f7768e,fg=#1a1b26,bold] 🔓 PASSTHROUGH #[bg=#33467c] " \; \
   refresh-client -S
 
 # Define the "off" key table - only F12 works to return (restore prefix + key-table)
@@ -119,8 +119,8 @@ bind -T off F12 \
   set prefix C-a \; \
   set key-table root \; \
   set -g mouse on \; \
-  set status-style "bg=#1e1e2e,fg=#cdd6f4" \; \
-  set status-left "#[bg=#89b4fa,fg=#1e1e2e,bold] #S #[bg=#1e1e2e] " \; \
+  set status-style "bg=#1a1b26,fg=#c0caf5" \; \
+  set status-left "#[bg=#7aa2f7,fg=#1a1b26,bold] #S #[bg=#1a1b26] " \; \
   refresh-client -S
 
 # When connected via SSH (likely nested inside local tmux), hide status bar
@@ -131,24 +131,24 @@ if-shell '[ -n "$SSH_TTY" ]' 'set -g status off'
 bind S set -g status
 
 # -----------------------------------------------------------------------------
-# Status bar - Catppuccin Mocha inspired
+# Status bar - Tokyo Night theme
 # -----------------------------------------------------------------------------
 set -g status-position bottom
-set -g status-style "bg=#1e1e2e,fg=#cdd6f4"
+set -g status-style "bg=#1a1b26,fg=#c0caf5"
 
 set -g status-left-length 40
-set -g status-left "#[bg=#89b4fa,fg=#1e1e2e,bold] #S #[bg=#1e1e2e] "
+set -g status-left "#[bg=#7aa2f7,fg=#1a1b26,bold] #S #[bg=#1a1b26] "
 
 set -g status-right-length 60
-set -g status-right "#[fg=#a6adc8]%Y-%m-%d #[fg=#cdd6f4]%H:%M #[bg=#a6e3a1,fg=#1e1e2e,bold] #h "
+set -g status-right "#[fg=#565f89]%Y-%m-%d #[fg=#c0caf5]%H:%M #[bg=#9ece6a,fg=#1a1b26,bold] #h "
 
 # Window status
-setw -g window-status-format "#[fg=#6c7086] #I:#W "
-setw -g window-status-current-format "#[bg=#313244,fg=#cdd6f4,bold] #I:#W "
+setw -g window-status-format "#[fg=#565f89] #I:#W "
+setw -g window-status-current-format "#[bg=#33467c,fg=#c0caf5,bold] #I:#W "
 
 # Pane borders
-set -g pane-border-style "fg=#313244"
-set -g pane-active-border-style "fg=#89b4fa"
+set -g pane-border-style "fg=#33467c"
+set -g pane-active-border-style "fg=#7aa2f7"
 
 # Message style
-set -g message-style "bg=#313244,fg=#cdd6f4"
+set -g message-style "bg=#33467c,fg=#c0caf5"