Ensure CSS updates after deploy

README.md

@@ -167,6 +167,18 @@ the template provides proper form control styles.
 
 Temporary file: [temp-input-colors.css](temp-input-colors.css)
 
+Developer note: DokuWiki serves a combined stylesheet via `lib/exe/css.php` and caches it.
+Cache invalidation is based on the mtimes of the source CSS/LESS files.
+If you deploy into a mounted/remote filesystem with a different clock, preserving mtimes can prevent
+automatic invalidation (making it look like your CSS changes don't load until you purge cache).
+
+`deploy.sh` avoids preserving mtimes by default to make CSS iteration smoother. If you explicitly want
+to preserve mtimes, use:
+
+```bash
+./deploy.sh --preserve-times
+```
+
 
 ## Features and usage