Follow-up from "implementa #40 - layout back_cover"

The following discussions from !32 (merged) should be addressed:

• @fauno started a discussion: (+1 comment)

  eventualmente a los colores deberiamos ponerles un nombre semantico porque si alguien quiere customizar los colores quizás blue se vuelve rojo

• @fauno started a discussion: (+2 comments)

  haganme acordar de convertir todo esto en woff2