Project Overview Develop a customized English vocabulary learning application with core functionalities similar to "Shanbei Words," but requiring personalized modifications to the learning modes and interaction design. Core Features (Shanbei-like Reference) Vocabulary System: Support selection or import of categorized word banks for various exams (e.g., CET-4/6, TOEFL, IELTS) and difficulty levels. Core Learning Flow: A complete cycle including "word recognition → multiple-choice/spelling tests → example sentence reinforcement → review." Review Mechanism: Intelligent review scheduling based on the Ebbinghaus forgetting curve. Data Analytics: Visualization of learning progress, vocabulary size, memory retention rates, and other metrics. User System: Account registration, login, and multi-device learning progress synchronization. Core Customization Requirements Learning Mode Innovation: Introduce more gamified level-up mechanisms, adjust spaced repetition algorithm parameters, or design entirely new test question types. Interaction/UI Design: Implement a fresh visual style (e.g., minimalist, immersive) or unique interactive workflows. Additional Features: Integrate AI-powered pronunciation scoring with speech feedback, short video explanations for words, or personalized vocabulary notebook management. Budget Costs to be confirmed upon further discussion and mutual agreement.