While you can always use the CSS tab for a page to style it with code, much of the styling of Aquro components can be done without writing any code at all.

When working on any component in the Page Builder, you can access its styling options either by clicking the paintbrush icon or by right clicking to open the component's contextual menu, then clicking Style.

Depending on the component you're trying to style, you may or may not have styling options available here.

In the case of the button.ui component selected in the above screenshots, I can easily change its colors...

Or head to the Styles tab and view all of the CSS classes the component can respond to, along with design properties within those classes:

You can change, add to, or remove these properties here without actually having to write any CSS!

If you do decide to write custom CSS and want to style these components, you can use the same class names that appear in the styles window here.