Q: How are styles and templates added for design and layout control?

A: eZ Publish is template-based in terms of the styling of the content presentation. All parts of the rendering of content to valid XHTML (for Web) is controlled with templates that define the XHTML that will be marked up. You can also have display logic there that will for example show the current path (breadcrumbs) for a given item enabling the building of rich interfaces.
The actual design is defined in CSS that is referenced by the XHTML in the templates. This ensures that you can easily re-use properly built templates across several projects/sites and just modify the CSS for different styling.