feat: add registration callout

index.qmd

@@ -20,4 +20,10 @@ The DigiHistCH24 conference on "Historical Research, Digital Literacy, and Algor
 
 This book of abstracts contains all the papers presented at the conference, providing a comprehensive overview of current research at the intersection of history and digital technology. These papers cover a range of topics, from innovative methodologies and software applications to the challenges of digital data management and algorithmic analysis in historical research.
 
-We are pleased to present this collection, which reflects the state of the art in digital history, and anticipate that the discussions it stimulates will make a significant contribution to the field.
+We are pleased to present this collection, which reflects the state of the art in digital history, and anticipate that the discussions it stimulates will make a significant contribution to the field.
+
+::: {.callout-tip}
+## DigiHistCH24 Registration
+
+We are looking forward to seeing you in Basel! Please don't forget to [register](https://conferences.unibas.ch/frontend/index.php?page_id=1424&booking_registration_action=show&booking_registration_controller=offer) for attending DigiHistCH24!.
+:::