I'm sort of guessing on this one ... my untested example below.
You should have the CSS style defined in your .css file for .successCSS
.successCSS{
font-family: arial;
font-size: 20px;
}
in your style sheet properties ... you would have borders, padding, background img, etc ...
Put this in your "functions.php" file located in your theme directory.
PHP Code:
<?php
function success_shortcode() {
return '<div class="successCSS">This is the text that always should be the same.</div>';
}
add_shortcode('success', 'success_shortcode');
?>
Then in your post ....
Blah Blah Blah
[success]
Blah Blah Blah
.