Mark, I did as you instructed:
<?php
add_action( 'admin_print_styles-post.php', 'my_admin_css' );
add_action( 'admin_print_styles-post-new.php', 'my_admin_css' );
function my_admin_css() {
?>
<style type="text/css">
#editorcontainer textarea#content { font-size:130%!important }
</style>
<?php
}
/**
* TwentyTen functions and definitions
*
* Sets up the theme and provides some helper functions. Some helper functions
* are used in the theme as custom template tags. Others are attached to action and
* filter hooks in WordPress to change core functionality.
*
* The first function, twentyten_setup(), sets up the theme by registering support
* for various features in WordPress, such as post thumbnails, navigation menus, and the like.
*
FWIW, I'm using the TwentyTen theme and no plugins affecting the editor. I have TinyMCE Advanced and Dean's FCKEditor plugin installed and deactivated (the factory default editor is sufficient for me). I activated each plugin separately and saw no change using TinyMCE Advanced, but do see a change with Dean's FDKEditor.
Frankly, I prefer the default, out of the box editor. I've used these plugins solely for the purpose of increasing the font size in the editor, which neither of them does without also affecting the published post.
Unless you have further advice which would spare me having to use the plugin solely to achieve the desired effect, I suppose I'll use Dean's FCKEditor since your recommendation appears to work (although it does not appear to be 130% the default size).
At any rate, thank you for your response.
