Tailwind.NET

Stylesheet • C# • Tailwind V4

## input.css Entry point for Tailwind CSS v4 compilation that imports the framework and defines theme customization. This file replaces the traditional `tailwind.config.js` approach from v3. The `@import` directive loads the Tailwind framework, while the `@theme` block defines custom design tokens using CSS custom properties. The `source()` parameter tells Tailwind where to scan for class usage in your application files. Theme tokens override Tailwind's defaults and can include colors, fonts, spacing, breakpoints, and other design system values. **Structure:** ```css @import "tailwindcss" source("../"); @theme { --font-sans: 'Outfit', system-ui, sans-serif; --font-mono: 'JetBrains Mono', monospace; } ``` **Critical Requirements:** - Must be UTF-8 encoded without BOM (Byte Order Mark) - `@import` must be the first line with no preceding text or comments - Theme customization happens in CSS, not JavaScript configuration files

HostedService • C# • .NET 9

## TailwindBackgroundService Hosted service that orchestrates Tailwind compilation lifecycle during application runtime. Implements `BackgroundService` to integrate with ASP.NET Core's application lifetime management. Executes initial CSS compilation on startup, starts the file watcher, then runs indefinitely until application shutdown. Handles graceful shutdown by responding to `CancellationToken` and properly disposing the watcher instance. Ensures compilation completes before the application starts serving requests. **Lifecycle:** 1. Application starts → Runs `InitialCompileAsync()` 2. Starts file watcher → Monitors for changes 3. Waits indefinitely → Keeps service alive 4. Application stopping → Disposes watcher and exits Automatically registered when using `app.UseTailwind()` in development environment.

Service • C# • .NET 9

## TailwindBinaryManager Automatically downloads and manages platform-specific Tailwind CLI binaries from GitHub releases. Detects the runtime operating system and architecture to select the correct binary variant. Downloads from the official Tailwind CSS GitHub releases to a configurable local directory (default `.tailwind/`). Handles binary caching to avoid repeated downloads, sets executable permissions on Unix-based systems, and supports manual URL override for custom binary sources or mirrors. **Key Methods:** - `EnsureBinaryAsync()` - Downloads binary if not present, returns path - `GetBinaryPath()` - Returns expected binary location - `DownloadBinaryAsync()` - Performs HTTP download with streaming **Platform Detection:** - OS: Windows, Linux, macOS - Architecture: x64, ARM64, ARMv7 - Automatic binary naming: `tailwindcss-{os}-{arch}[.exe]`

Service • C# • .NET 9

## TailwindCompiler Executes the Tailwind CLI binary as a process and manages compilation lifecycle. Builds command-line arguments from `TailwindOptions` configuration and spawns the Tailwind CLI process with proper output/error stream handling. Captures stdout and stderr for logging, tracks compilation time, and returns success status based on exit code. Handles process lifecycle including output streaming to prevent blocking, cancellation support via `CancellationToken`, and proper error reporting with detailed exit codes and error messages. **Key Methods:** - `CompileAsync()` - Executes compilation and returns success boolean - `BuildArguments()` - Constructs CLI arguments from configuration Typical command generated: `tailwindcss -i "Tailwind/input.css" -o "wwwroot/css/tailwind.css" --content "..." --minify`

Options • C# • .NET 9

## TailwindOptions Configuration model for Tailwind CSS compilation and file watching behavior. Defines all customizable settings including input/output paths, content scanning patterns, watch behavior, and CLI arguments. All properties have sensible defaults for immediate use. **Key Configuration:** - **Binary Management** - Version, download URL, and storage location - **File Paths** - Input CSS, output CSS, and content scanning paths - **Watch Behavior** - File patterns to monitor and debounce delay - **Compilation** - Minification toggle and additional CLI arguments Supports both convention-based defaults (works immediately with included `input.css`) and full customization for complex project structures.

Service • C# • .NET 9

## TailwindWatcher Monitors file system changes and triggers CSS recompilation with debouncing to prevent excessive builds. Creates `FileSystemWatcher` instances for each pattern in `WatchPatterns` and responds to file changes, creations, and renames. Uses a configurable debounce delay (default 300ms) to batch rapid changes into a single compilation. Thread-safe compilation locking ensures only one build runs at a time. Subsequent file changes cancel pending debounces and queue a new compilation after the current one completes. Ignores changes to the output CSS file to prevent infinite compilation loops. **Key Methods:** - `Start()` - Initializes file watchers for configured patterns - `InitialCompileAsync()` - Runs compilation on application startup - `Dispose()` - Cleans up watchers and cancellation tokens

Extension • C# • .NET 9

Tailwind Service Extensions