Hi and thank you for reply
i am always create styles from kentico stylesheet section in development.
the style included correctly and every thing works fine except that transition attribute removed by system and not applied to tag (by using firebug i see transition css attr removed and does not exist) While it is exist in style sheet defined for the site.
I place it directly by using
<link href="/CMSPages/GetResource.ashx?stylesheetname=SiteStyle" rel="stylesheet" media="all" />
When you say "when i look at my style sheet it is exist", it is served on your output cms page?
the mention style is define inside SiteStyle , but after the page rendered , style transition attr not applied to the htm tag.by inspecting styles using firebug i found that this attribute removed however by cms or by browser or... .