Technical Specification: Online Line Graph Generator

1. Overview

A web-based tool designed to allow users to generate professional-grade line graphs from input data. The tool emphasizes privacy, speed, and simplicity, operating entirely client-side using Chart.js via CDN.

2. Core Features

• Data Input Interface: A text area allowing users to paste CSV data or manually define X and Y coordinate pairs.
• Real-Time Rendering: The chart updates instantaneously as the user modifies data or configuration settings.
• Customization Options:
  • Chart Title, X-Axis Label, and Y-Axis Label inputs.
  • Line color and point style selection.
  • Toggle for grid lines, legends, and tooltip visibility.
  • Interpolation/Smoothing toggles (monotone, linear, stepped).
• Export Utility: Download button to save the current chart as a high-quality PNG or SVG image using the canvas API.
• Responsive Design: Auto-adjusts chart container dimensions for mobile, tablet, and desktop viewports.

3. UI/UX Layout

• Header: Simple, clean navigation with the tool title and an 'About' modal link.
• Primary Container (Sidebar/Panel Layout):
  • Left Panel (Inputs): Data input field (Textarea), configuration fields (inputs, toggles, color pickers).
  • Right Panel (Preview): A clean, card-based container holding the canvas element where the chart renders.
• No Footer: The design terminates cleanly at the bottom of the content area.

4. Visual Aesthetic & Design System

• Palette: Use a clean, light-mode palette: #ffffff (background), #f3f4f6 (secondary bg), #374151 (primary text), #6366f1 (accent color for buttons and primary lines).
• Styling: Tailwind CSS classes for spacing, typography, and shadow effects.
• Typography: Sans-serif, human-readable fonts (Inter or System UI).
• Animations: Subtle fade-in animations when the chart updates and smooth transitions for button hover states.

5. Technical Directives

• Single-File Architecture: All CSS and JavaScript must be embedded within a single .html file. No separate files.
• External Dependencies: Utilize CDN links for Chart.js and Tailwind CSS. Do not bundle dependencies.
• Storage Restrictions: NO localStorage, sessionStorage, or IndexedDB. Use application-state variables to manage data in-memory.
• Browser Security: Ensure all external links contain target="_blank" rel="noopener noreferrer". Avoid alert(), prompt(), and confirm(). Use custom DOM-based modals for user interaction.
• Performance: The app must execute entirely in the browser. Large dataset handling should be optimized by limiting the maximum number of data points if necessary to maintain a 60fps frame rate for interactions.