WIP Permission Inquiry: Using Stardew Valley Assets in a Non-Commercial Personal Finance App

[malatang]

Hello everyone!
I'm currently developing a strictly non-commercial personal finance tracking app (tech stack: React + Vite + Hono + PostgreSQL) to manage daily expenses. To enhance the user experience, I'd love to incorporate Stardew Valley's iconic art style into the interface.
However, creating a full set of original pixel-art assets from scratch is extremely time-consuming. Therefore, I'd like to respectfully ask ConcernedApe and the community:

Is it permissible to use official Stardew Valley assets (e.g., item sprites, UI elements) in a non-commercial personal project?

Key clarifications about my project:

• Absolutely no commercial use (no subscriptions, no in-app purchases, no ads)
• Will only accept voluntary donations post-launch (e.g., "buy me a coffee" model), with all core features remaining free
• Currently in early development.
• Here are some of my engineering files and screenshots of the current run

If using official assets isn't allowed, I’d greatly appreciate suggestions for alternative approaches or style-mimicking techniques! All feedback on development or feature design is welcome—thank you in advance!