What is the author's style in Between Shades of Gray by Ruta Sepetys?

The story is written in a straightforward manner from the perspective of a fifteen-year-old girl. Lina Vilkas. The written is clear and easy to follow. There are some words in Russian but these are typically explained so the reader can understand what's being said. An often-repeated Russian word is "davai." The Russians use this word repeatedly.