# 🦉 Animations 🦉 Animation is a complex topic. There are many different use cases, and many solutions and technologies. ## Simple CSS effects Sometimes, using pure CSS is enough. For these use cases, Owl is not really necessary: it just needs to render a DOM element with a specific class. For example: ```xml ``` with the following CSS: ```css .flash { transition: background 0.5s; } .flash:active { background-color: #41454a; transition: background 0s; } ``` will produce a nice flash effect whenever the user click (or activate with the keyboard) the button. ## CSS Transitions (single element) A more complex situation occurs when we want to transition an element in or out of the page. For example, we may want a fade-in and fade-out effect. The `t-transition` directive is here to help us (see [QWeb documentation](doc/qweb.md#t-transition-directive)).