Make a new tiddler and set the tags field to $:/tags/Stylesheet
Set the type field to Stylesheet (text/css)
Then paste the following CSS styles:
.tc-dropzone em { color: blue; }
.tc-dropzone strong { color: red; }
Save the tiddler: all italics should be blue, all bolds should be red. This is what I got when I put it in a tiddler named “Custom Format”:
