Inconsistency in the font size

This issue being in different projects changes the game, that should have been explained in your post.

The first thing I would do is rename the CSS in one project and then copy in the other CSS and apply it to a topic. Does that change things? The idea here is that whilst the CSS files may have the same name, it does not mean the content is the same.

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I'm stuggling to think how this is happening. 

You say 13 but what measurement, points? That should look like this in source view.

<p><span style="font-size:13pt">This </span>

Is that what you see in both? If not post the code for the affected text in the two topics.

Try applying your CSS in the output.

In the topic that looks wrong, check all the source code for something else overriding your styles.

Come back if stuck.

________________________________________________________

My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.

Are you looking at the font size in the output of different projects or the RH project topics themselves? Just unclear where you're referring to.

Are you apply the font size from the CSS or are you applying inline styling?

Have you checked both topics are using the same CSS file?

Have you applied a different CSS in the preset?

________________________________________________________

My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.