A modern, responsive web app for quickly calculating proportions. Features automatic light/dark theme, multilingual support (Italian/English), animated error handling, operation history, and a polished user interface. All computations happen instantly in your browser.

• Proportion calculation UI: Calculate ratios in the form X : Y = Z : A with one unknown (x or X). Enter three known values, set one unknown — get your solution instantly.
• Responsive design: Works flawlessly on desktop, tablet, and mobile. Adapts layout for both landscape and portrait modes.
• Automatic light/dark theme: Matches your system or browser preference with a smooth animated transition.
• Multilingual (IT/EN): Automatically detects your browser language — Italian for Italian settings, English for everything else.
• Intuitive error handling: Input checking ensures only one unknown is present. Animated modal popups explain errors or invalid inputs.
• Calculation history: All operations are listed at the bottom of the page for reference, with results highlighted in green.
• Animated highlights: The solved field is illuminated with a green border for clarity.
• User help: Dedicated help button (lifebuoy icon top-right) shows a friendly usage guide in a popup.
• Reset button: After each calculation, a prominent reset button lets you quickly clear all fields and start fresh.
• No dependencies: Runs entirely client-side, no data upload or server required.

1. Open the app in your browser (just open the link above).
2. Enter three numeric values in the main proportion layout:
   Value : Base = Value : Base
3. In the field you want to solve, type x (or X). Only one unknown is allowed.
4. Click the Calcola! / Calculate! button.
5. The app checks your inputs:
   • If there's an error (multiple unknowns, missing values, etc.) a modal popup appears explaining the issue.
   • If valid, the app calculates the missing value, highlights it in green, and adds the operation to the cronology/history below.
6. Optional: Click the Reset button to clear the interface and start a new calculation.
7. Tap the lifebuoy icon in the top right for instant help.

• Modern style: rounded corners, soft shadows, visually balanced typography and spacing.
• All elements scale gracefully for mobile and desktop.
• Input boxes dynamically resize according to content.
• Error and help popups with smooth entrance animations.
• History section stays fixed at the bottom with each result colored for quick identification.

• The interface remains horizontal as long as possible, guaranteeing optimal readability.
• On very narrow screens, inputs reorder vertically for clarity and optimal space usage.
• Touch targets and controls are sized for comfort.
• All features and animations remain available on mobile devices.

• All processing is done locally in your browser.
• No input is ever sent to a server.
• No data is stored except in-session for the live history display.

• Get proportion solutions instantly, with clear explanation if something’s wrong.
• Use on the go — perfect for students, professionals, or anyone dealing with ratios/conversions.
• Works everywhere, no registration, no installation, no dependencies.

Open issues, request features, and help improve the project! All contributions and suggestions warmly welcomed.