Update FccFastSimGeneration.md

Author: gganis

fast-sim-and-analysis/FccFastSimGeneration.md

@@ -29,12 +29,12 @@ which fccrun
 # the output might differ, but shouldn't be empty
 /cvmfs/sw.hsf.org/spackages/linux-centos7-broadwell/gcc-8.3.0/fccsw-develop-q57ahua7lm65fvxnzekozih4mgvzptlx/scripts/fccrun
 ```
-{% important %}
 
-You will need to source the /cvmfs/fcc.cern.ch/sw/latest/setup.sh script everytime you want to use the software.
+{% callout "Nota Bene" %}
 
-{% endimportant %}
+You will need to source the /cvmfs/fcc.cern.ch/sw/latest/setup.sh script everytime you want to use the software.
 
+{% endcallout %}
 
 ## Generators