CSS Picker (beta)
Simple for usage extension will allow you to copy styles and behavior of selected element in ease. It is able to collect whole bunch of CSS rules related to selected DOM element and has simpliest interface and pleasant design. Chrome debugger is not always able to collect all rules in one place, but CSS Picker is! Rules are separated with tabs, thus you can easily choose what exactly you need to copy whether it is :pseudo_class, whether ::pseudo_element or simply pack of rules related to single element.