Understand the ramifications of setting the value of a CSS property to something other than the default, or of updating that value.
The CSS Triggers site lists CSS properties alphabetically, and lets you know whether changing their values will trigger layout, print or composite work. Clicking on a property brings up detailed information about what will happen and what the costs might be.
This reference, created by Paul Lewis, is created to allow developers to more readily understand the ramifications of changing their styles. PS: At the moment this only works for Chrome.CSS Triggers