CodeBrix.StyleSheetParse.MitLicenseForever 1.0.238.81

CodeBrix.StyleSheetParse

A fully managed, cross-platform CSS stylesheet parsing library for .NET. CodeBrix.StyleSheetParse has no dependencies other than .NET, and is provided as a .NET 10 library and associated CodeBrix.StyleSheetParse.MitLicenseForever NuGet package.

CodeBrix.StyleSheetParse supports applications and assemblies that target Microsoft .NET version 10.0 and later. Microsoft .NET version 10.0 is a Long-Term Supported (LTS) version of .NET, and was released on Nov 11, 2025; and will be actively supported by Microsoft until Nov 14, 2028. Please update your C#/.NET code and projects to the latest LTS version of Microsoft .NET.

CodeBrix.StyleSheetParse is a fork of the code of the open source ExCSS library - see below for licensing details.

Installation

dotnet add package CodeBrix.StyleSheetParse.MitLicenseForever

Note that the NuGet package ID and the namespace are different - there is no package named plain CodeBrix.StyleSheetParse:

• NuGet package ID: CodeBrix.StyleSheetParse.MitLicenseForever
• Assembly and namespace: CodeBrix.StyleSheetParse - i.e. using CodeBrix.StyleSheetParse;

Everything public lives in that one namespace. The package has no NuGet dependencies and no native libraries; it depends only on the .NET base class library. XML documentation (IntelliSense) ships alongside the assembly.

CodeBrix.StyleSheetParse supports:

• CSS stylesheet parsing from strings and streams
• Async parsing with cancellation support
• CSS selector parsing and specificity calculation
• Style rule, media query, and at-rule modeling
• @keyframes, @font-face, @supports, @container, @page, @import, @namespace, @charset, @document, @viewport rules
• Style declaration reading and manipulation
• CSS serialization (converting parsed stylesheets back to CSS text)
• Configurable parser tolerance (unknown rules, invalid selectors, comments, etc.)
• Many more...

CodeBrix.StyleSheetParse is a parser and object model, not a rendering or styling engine. It does not match selectors against a document, compute cascaded or inherited styles, validate CSS against a specification, resolve @import URLs or var() custom properties, or minify CSS. The one built-in formatter emits readable output; implement IStyleFormatter for anything else.

Sample Code

Parse a CSS Stylesheet

using CodeBrix.StyleSheetParse;

var parser = new StylesheetParser();
var stylesheet = parser.Parse("h1 { color: red; font-size: 24px; }");

foreach (var rule in stylesheet.StyleRules)
{
    Console.WriteLine($"Selector: {rule.SelectorText}");
    Console.WriteLine($"Color: {rule.Style.Color}");
}

Parse a CSS Selector and Check Specificity

using CodeBrix.StyleSheetParse;

var parser = new StylesheetParser();
var selector = parser.ParseSelector("div.highlight > span#title");

Console.WriteLine($"Selector: {selector.Text}");
Console.WriteLine($"Specificity: {selector.Specificity}");

Serialize a Stylesheet Back to CSS

using CodeBrix.StyleSheetParse;

var parser = new StylesheetParser();
var stylesheet = parser.Parse("h1 { color: red; } @media screen { p { font-size: 14px; } }");

string css = stylesheet.ToCss();
Console.WriteLine(css);

Documentation

The NuGet package includes AGENT-README.txt, a complete API reference and usage guide written for AI coding agents - point your agent at that file when it is writing code against this library.

Additional sample code and usage examples are available in the CodeBrix.StyleSheetParse.Tests project: https://github.com/ellisnet/CodeBrix.StyleSheetParse/tree/main/tests/CodeBrix.StyleSheetParse.Tests

Note that the test project has InternalsVisibleTo access to the library, so some of what it calls (for example Stylesheet.Rules, MediaRule, SupportsRule, KeyframeRule and parser.ParseDeclaration) is internal and is not available to package consumers.

License

The project is licensed under the MIT License. see: https://en.wikipedia.org/wiki/MIT_License

All code originating from ExCSS was included as allowed by the MIT License permissible open source software license - as of ExCSS version 4.3.1. This project (CodeBrix.StyleSheetParse) complies with all provisions of the source code license of ExCSS v4.3.1 (MIT License).