The provided code snippet is valid XHTML 1.0 Transitional markup.
We agree that using external CSS styles is better than using inline styles, but in some cases it is important to ensure that a certain style will be applied in all cases, no matter what the skin settings are (e.g. Skin turned off). There are also scenarios in which different browsers require different styles and moving such styles to external CSS files will require CSS hacks - something, which should be avoided even more. Finally, external CSS styles are more easily overridden from custom application styles, compared to inline styles.
On a side note, removing all inline styles and moving them to the external CSS will tend to increase the control's complexity and reduce maintainability from developer's point of view. Inline styles are something which generally "does not exist".
Surely, we always keep in mind the HTML/CSS best practices and apply them in the process of control evolution and improvement.
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