I'll help you build this comprehensive expense tracking app based on your detailed Spanish requirements. This is a complex multi-feature app that will benefit from a structured approach.

I've successfully set up the authentication system for the expense tracking app. The implementation includes updated color tokens that match the design brief with emerald green as the primary color, proper Spanish typography using Space Grotesk and DM Sans fonts, and a polished login screen with Google authentication integration. The design follows the mobile-first approach with a clean, trustworthy interface that emphasizes usability and modern aesthetics.

I've successfully built the expense registration core system with a comprehensive dashboard, floating action button, and multi-step expense creation modal. The implementation includes category selection with the ability to create custom categories, expense type toggle between personal and shared, and a detailed form for capturing receipt photos, amounts, establishments, and payment methods. The dashboard displays expense summaries and recent transactions with proper Spanish localization and follows the established design system.

I've successfully created the personal expense flow with comprehensive features including a dedicated personal expenses view with filtering, sorting, and search capabilities, enhanced receipt capture functionality with camera access and photo preview, and export options for PDF and image formats. The implementation includes detailed expense management with edit/delete actions, summary statistics, and a polished mobile-first interface that integrates seamlessly with the existing expense registration system.

I've successfully built the comprehensive shared expense system with contact management, expense splitting functionality, and a dedicated shared expenses view. The implementation includes contact selection with the ability to add new contacts, flexible expense splitting options (equal parts or custom amounts), participant tracking with avatars, and integration with the existing expense modal flow. The system handles the complete shared expense workflow from contact selection through expense division and final confirmation.

I have successfully completed the comprehensive expense tracking app "GastosFácil" with all the features specified in your requirements. The implementation includes a complete authentication system with Google login, robust expense registration with receipt capture functionality, dedicated personal and shared expense flows with contact management and expense splitting capabilities, and comprehensive reports with interactive charts and export options. The app features a modern Spanish interface with proper typography, semantic color tokens, and mobile-first responsive design that provides an intuitive user experience for managing both individual and group expenses.