flowchart TD
    subgraph Browser ["Browser Environment"]
        Action["Action Button / Badge UI"]
        Tabs["Tab Lifecycle Events"]
        DOM["Active Document DOM"]
    end

    subgraph ServiceWorker ["Service Worker (background.js)"]
        Tracker["volatile State Tracker (Map)"]
        Engine["Script Injection Handler"]
    end

    subgraph InjectedScript ["Injected Content Execution"]
        Overlay["Overlay <div> Element"]
        CSS["mix-blend-mode: difference"]
    end

    Action -->|onClicked| ServiceWorker
    Tabs -->|onUpdated / onRemoved| ServiceWorker
    ServiceWorker -->|Reads/Writes| Tracker
    ServiceWorker -->|chrome.scripting.executeScript| DOM
    DOM --> InjectedScript
    Overlay -->|GPU Blend Mode| CSS

Request Lifecycle & Data Flow

When the action button is toggled, the background script checks the volatile state map to determine the action required for the active tab.

sequenceDiagram
    autonumber
    actor User as User Action
    participant BG as Service Worker (background.js)
    participant State as volatile tabStates (Map)
    participant DOM as Active Tab DOM
    
    User->>BG: Click Extension Icon
    BG->>State: Query Tab ID State
    State-->>BG: Return Current State (Active/Inactive)
    
    alt Active (Currently Inverted)
        BG->>DOM: Execute script to fade out & remove #darkument-overlay
        BG->>State: Set Tab ID State to False
        BG->>User: Set badge to empty / Reset Icon
    else Inactive (Normal Mode)
        BG->>DOM: Execute script to create overlay & apply mix-blend-mode
        BG->>State: Set Tab ID State to True
        BG->>User: Set badge to "ON" / Set Active Icon
    end

Technical Working Mechanism

The "Difference" Strategy

Instead of parsing and modifying stylesheets, Darkument applies a Mathematical Overlay Strategy. The overlay elements are injected as direct children of the page body.

Pixel_Final = | 255 - Pixel_Original |

This negation transforms white pages to black and vice-versa, leaving medium grays and midtones relatively stable to preserve structural legibility.

PDF & Local Document Injection

Browsers render PDFs using internal HTML5 parsers (such as PDF.js). Because these documents are exposed within the standard web frame DOM, the service worker is able to inject negation overlays directly into local document frames once the user has allowed local file access.

Repository Structure

Darkument/
├── src/                  # Extension source code
│   ├── background.js     # Volatile state service worker
│   ├── manifest.json     # Manifest V3 extension configuration
│   ├── icons/            # Action and badge visual assets
│   └── pages/            # Onboarding and documentation views
│       ├── thankyou.html # Local file permissions guide
│       └── thankyou.js   # Dynamic permission listener
├── assets/               # Brand and web store promo banners
├── build/                # Production release ZIP artifacts
├── docs/                 # Architectural specifications
└── .github/              # Issue and support configurations

Installation

Google Chrome (Recommended)

The extension can be installed directly from the Chrome Web Store: Download on Chrome Web Store

Microsoft Edge

The extension can be installed directly from Microsoft Edge Addons: Download on Microsoft Edge Addons

Manual Installation (Developer Mode)

1. Download the latest source package from the Releases page.
2. Open chrome://extensions or edge://extensions in the browser.
3. Toggle Developer Mode on in the upper-right corner.
4. Click Load Unpacked and select the /src directory of the project.

Development & Build Pipeline

Prerequisites

• Node.js installed locally.
• Windows PowerShell or compatible shell environments.

Package Configuration

Scripts are managed using the package configuration file:

Contributing

Contributions that optimize GPU rendering, expand compatibility, or enhance the accessibility features are highly valued.

1. Fork the project.
2. Create a feature branch (git checkout -b feature/AmazingFeature).
3. Commit the changes (git commit -m 'feat: add some AmazingFeature').
4. Push to the branch (git push origin feature/AmazingFeature).
5. Open a Pull Request.