by kirupa | 20 October 2016
When interacting with UIs, a lot of the animations you will see won't be of the CSS animation kind with their predefined keyframes. They will instead be reactions to the things you are doing. Examples of such reactions include a link underlining when you hover it, a menu flying in when you tap on a button, a text element getting bigger when it has focus, and a billion other things. For animating these kinds of situations, you have what are known as CSS Transitions.
This is a companion discussion topic for the original entry at http://www.kirupa.com/html5/introduction_css_transitions.htm