Note: this text prompt is auto-generated as a starting point. Please edit and refine the details for your lesson context.

USER TASK SPECIFICATION:

Create a complete, functional HTML5 interactive titled **"Number Line Estimation Game"**.

GENERAL REQUIREMENTS:
- Self-contained front-end using **HTML, CSS, and JavaScript only** (no external frameworks required).
- Designed for **browser use on laptops, tablets, and phones** (responsive layout).
- Clear visual layout with a **main interactive area** and a **side/top panel** for instructions and feedback.
- Include basic **interactivity appropriate to the title** (e.g., game/simulation/quiz/visualization).
- Provide **immediate feedback** where meaningful (correct/incorrect, hints, progress indicators, etc.).
- Use simple, student-friendly visual design and readable text.

SUGGESTED STRUCTURE (EDIT AS NEEDED):
1. **Learning Goal & Context**
   - Briefly describe the learning objective(s) for "Number Line Estimation Game".
   - Example: "Students will be able to ..." (fill in based on your subject and level).

2. **Core Interactive Mechanics**
   - Describe the main interaction for this activity (e.g., drag-and-drop, multiple-choice, slider-based simulation, matching pairs, timeline manipulation, etc.).
   - Explain how the learner will use the interactive to achieve the learning goal.

3. **Feedback & Scoring (if applicable)**
   - Specify how the interactive should respond to correct vs incorrect actions.
   - Indicate whether there should be a score, attempts counter, or summary message at the end.

4. **Interface Layout**
   - Describe the main UI regions (e.g., top instructions bar, left control panel, right visualisation area, bottom feedback/status bar).
   - Indicate any important buttons (Start, Reset, Check Answer, Next, Help, etc.).

5. **Accessibility & Responsiveness**
   - Ensure buttons and text are large enough for touch devices.
   - Prefer high-contrast colors and clear labels for all controls.

6. **Extra Notes (Optional)**
   - Any subject-specific rules, constraints, or content that must be included (e.g., specific question sets, scenario details, or data sets).

DEVELOPER IMPLEMENTATION NOTES:
- Organise the code into three files in this folder:
  -  – structure and main containers for "Number Line Estimation Game".
  -  – layout, colours, and responsive design.
  -  – interactive logic, event handlers, and state management.
- Ensure the interactive runs fully **offline** once these files are loaded in a browser.