Primeui. What css and js files to include

Question

I cannot make buttons look like they are on the demo page. Unfortunatelly, in documentation not even a word is said about exactly what stylesheets to include. And now whatever I do, buttons do not change their styles and look like standard jquery buttons. This is what I include to my page:

1. jquery-ui.min.css
2. jquery-ui.theme.min.css
3. primeui-1.1-min.css
4. themes/ui-lightness/theme.css <-- one of primeui themes
5. jquery-2.3.1.min.js
6. jquery-ui.min.js
7. production/primeui-1.1-min.js

All files are loaded well, however, when I do something like

el.puibutton()

as a result I get a general jquery button.