Update intro.html

Added space and centered the NSF Support and Acknowledgement Disclaimer.

_includes/dc/intro.html

@@ -5,7 +5,9 @@
   apply skills learned to their own research.
   Participants will be encouraged to help one another
   and to apply what they have learned to their own research problems.
-
+</p>
+<p align="center">
+  <em>
   NSF Acknowledgement of Support and Disclaimer:  This material is based upon work supported by the National Science Foundation under Grant No. 2217346. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. 
 </p>
 <p align="center">