Test your CSS changes

The style sheet files explained earlier in this section contain many style definitions, which makes it difficult to map the CSS classes to what you see in the application at runtime. To make this task easier, we recommend that you use the DevTools for Chrome, Web Inspector for Safari, or Firebug for Firefox to inspect the UI elements you want to style.

Once you have selected an element, you can view all of the CSS properties that apply to it, then change the CSS and watch your changes take immediate effect. This allows you to quickly and easily find the appropriate CSS to edit and gives you the ability to preview your changes in real time.