Minimalist UX/UI Design for Cross-Platform App

I am looking for a modern and minimalistic design for my mobile and web app. This design should be compatible across iOS, Android and Web platforms. The core functionalities of the app include user authentication, in-app purchases and push notifications.

Ideal skills and experience for the job include:
- Extensive experience in UX/UI design, particularly for mobile and web apps
- A strong portfolio demonstrating minimalist design aesthetics
- Proven track record of designing apps with user authentication, in-app purchases and push notifications
- Proficiency in using design software such as Sketch, Adobe XD or Figma
- Understanding of cross-platform design principles
- Excellent communication skills for understanding project requirements and delivering on time