review taxonomy usability themes

Hello all, here I introduce you my cuentos infantiles site.
It is a site written in spanish, where I post original short stories for children, created to educate in values and ethics. It is not a commercial site that has been in production over half a year, and right now I would like to receive feedback about these points I am concerned about:
- Usability and navigation: I am not sure if they are clear and simple enough, nor even if the site's goals are well showm.
- Theming: I wonder if the selected theme is adequate for the content and structure of the site. Especifically I would like feedback regarding the usage of a 3 column layout.
- Taxonomies presentation. Taxonomies are key for this site, as taxonomy and tagadelics are the core orgonization of the site. However, I would like to receive feedack about how taxonomies are presented and displayed
Also, if someone want to provide suggestions of useful blocks and so on, I would be glad to read them

thank you very much for your feedback!