Lovable Prompt Creator - AI Prompt Generator

```markdown
PROJECT DEFINITION
Create a messaging interface in Roblox using Lua that allows players to send messages to each other. The interface should have a clean and minimalist design, featuring a toggle for dark and light themes, input fields for the recipient's username and message, and a send button. The purpose is to provide a user-friendly way for players to communicate within the game environment.

DESIGN REQUIREMENTS
- Visual Style: minimalist - Clean, simple design with plenty of white space, minimal color palette, and focus on typography
- Color Mode: Light theme with dark text on light backgrounds
- Primary Color: #1978E5 (accent for buttons, links, highlights)
- Typography: Use Inter from Google Fonts for headings, Inter for body text and UI elements
- Border Radius: 8px (moderately rounded) for buttons, cards, and inputs

TECH STACK & CONSTRAINTS
- Language: Lua
- Framework: Roblox Studio
- Constraints: The UI must be responsive and easily adaptable to different screen sizes. Ensure that the theme toggle functionality works smoothly and the transitions are visually appealing.

BREAKDOWN INTO TASKS
1. Set up the Roblox environment with a ScreenGui for the UI.
2. Create the main frame with a draggable feature.
3. Implement the header with the title and theme toggle button.
4. Add input fields for the recipient and message.
5. Create a send button that triggers message sending functionality.
6. Implement the dark/light mode toggle functionality including transitions.
7. Ensure proper event handling for sending messages.

IMPLEMENTATION GUIDANCE
1. Create a ScreenGui and main frame using `Instance.new`.
2. Set the properties for the main frame, including size, position, and background color.
3. Create a header frame, add a TextLabel for the title, and a TextButton for the theme toggle.
4. Create TextBox instances for recipient input and message input, and set their properties for appearance.
5. Create a TextButton for sending messages and define its properties.
6. Write a function to handle the theme change using TweenService for smooth transitions.
7. Connect the button click events to the respective functions for toggling themes and sending messages.

ITERATION STRATEGY
- After initial implementation, test the functionality of the toggle and message sending.
- Gather feedback on the UI design and usability.
- Make adjustments to the layout, colors, and transitions based on user experience.

TESTING & VALIDATION
- Test the UI on various screen sizes to ensure responsiveness.
- Validate the theme toggle functionality works correctly by checking the color changes.
- Ensure that the message sending feature accurately captures input and outputs the expected results in the console.
- Conduct user testing to identify any usability issues and refine the interface accordingly.
```