Q: How to transition to height:auto? A: Transition max-height instead!
With this bookmarklet you can click a html element and get and edit an XPath/CSS Path expression to it.
browserübergreifend farbverläufe zusammenklicken
When applying CSS3 inset box-shadow or border-radius directly to the image element, the browser doesn't render the CSS style perfectly. However, if the image is applied as background-image, you can add any style to it and have it rendered properly.
I present you with the CSS Stress Test bookmarklet.