Planned hero entry points: walls glow and pulse red, with a pulsing red light

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

DESIGN.md

@@ -82,7 +82,7 @@ An original dungeon management game (genre: dungeon building & defence) that run
 - Each wave picks an **entry point** on the border of the realm facing the hero gate: few towers/creatures, no reinforced walls and a short way are attractive, entry points of recent waves are avoided, plus some randomness
 - Waves of **6+ heroes split into two groups** with different entry points (the paladin goes with the bigger group)
 - Heroes first tunnel to their entry point, then go for the core
-- **Warning** 30 s before: scout message with the direction(s) and blinking markers on the minimap
+- **Warning** 30 s before: scout message with the direction(s), blinking markers on the minimap and the **walls at the entry points glowing and pulsing red** (plus a pulsing red light) until the wave has broken in
 
 ## Goal
 - **Victory**: destroy the Hero Gate