This is the 11372nd most frequent Russian word.
дизайна
"Дизайна" in English means "design" (genitive case).
Here, 'дизайна' specifies the object of the principles being discussed, indicating a genitive case usage.
Эта книга рассказывает о принципах современного дизайна.
This book talks about the principles of modern design.
In this sentence, 'дизайна' is used in the genitive case to provide possession concerning the color palette.
Цветовая палитра этого дизайна очень гармонична.
The color palette of this design is very harmonious.
Here, 'дизайна' again conveys possession, associating the topic with urban design.