added maintenance note

Author: zopyx

web/content/intro.rst

@@ -7,6 +7,13 @@
    :class: banner
 
 
+.. note::
+
+  print-css.rocks is currently (as of 2025) no longer updated.
+  The site remains online for the time being but do not expect any
+  future updates.
+
+
 Introduction to PrintCSS and CSS Paged Media
 ============================================
 
@@ -16,6 +23,8 @@ and layout information is kept in cascading stylesheets (CSS).
 It will also show the results produced by different tools with identical
 data, providing an impression of functionality and output quality.
 
+
+
 What is CSS Paged Media
 -----------------------