use our callout template

Author: mr-c

_episodes/14-runtime.md

@@ -30,11 +30,13 @@ Any [expressions](../13-expressions/index.html) like `$(inputs.message)` are
 expanded by the CWL engine before creating the file;
 here inserting the value at the input `message`.
 
-> **Tip:** The _CWL expressions_ are independent of any _shell variables_
+> ## Tip
+> The _CWL expressions_ are independent of any _shell variables_
 used later during command line tool invocation. That means that any genuine
 need for the character `$` must be **escaped** with `\`,
 for instance `\${PREFIX}` above is expanded to `${PREFIX}` in the generated file
 to be evaluated by the shell script instead of the CWL engine.
+{: .callout}
 
 To test the above CWL tool use this job to provide the input value `message`: