Release 1.0.1

.config/dotnet-tools.json

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "isRoot": true,
+  "tools": {
+    "fallout.cli": {
+      "version": "11.0.18",
+      "commands": [
+        "fallout"
+      ]
+    }
+  }
+}

.nuke/build.schema.json → .fallout/build.schema.json

@@ -26,7 +26,6 @@
       "enum": [
         "Clean",
         "Compile",
-        "CopyFiles",
         "CreatePackage",
         "Default",
         "Package",
@@ -49,7 +48,7 @@
         "Quiet"
       ]
     },
-    "NukeBuild": {
+    "FalloutBuild": {
       "properties": {
         "Continue": {
           "type": "boolean",
@@ -103,6 +102,13 @@
         "Verbosity": {
           "description": "Logging verbosity during build execution. Default is 'Normal'",
           "$ref": "#/definitions/Verbosity"
+        },
+        "BuildProjectFile": {
+          "type": [
+            "null",
+            "string"
+          ],
+          "description": "Path to the build project (.csproj) relative to the repository root. Defaults to 'build/_build.csproj' when unset. Read by the Fallout global tool's in-tool runner."
         }
       }
     }
@@ -116,11 +122,11 @@
         },
         "Configuration": {
           "type": "string",
-          "description": "Configuration to build - Default is 'Debug' (local) or 'Release' (server)",
           "enum": [
             "Debug",
             "Release"
-          ]
+          ],
+          "description": "Configuration to build - Default is 'Debug' (local) or 'Release' (server)"
         },
         "ReleaseNotesFilePath": {
           "type": "string",
@@ -133,7 +139,7 @@
       }
     },
     {
-      "$ref": "#/definitions/NukeBuild"
+      "$ref": "#/definitions/FalloutBuild"
     }
   ]
 }

.github/FUNDING.yml

@@ -1,4 +1,4 @@
 # These are supported funding model platforms
 
 github: FlorianRappl
-custom: https://salt.bountysource.com/teams/anglesharp
+custom: ['https://www.paypal.me/FlorianRappl', 'https://buymeacoffee.com/florianrappl']

.gitignore

@@ -59,7 +59,8 @@ local.properties
 [Dd]ebug/
 [Rr]elease/
 [Bb]in/
-[Bb]uild/
+build/bin/
+build/obj/
 [Oo]bj/
 
 # Visual Studio 2015 cache/options directory
@@ -171,7 +172,8 @@ Desktop.ini
 *.egg
 *.egg-info
 dist
-build
+build/bin
+build/obj
 eggs
 parts
 var
@@ -195,5 +197,5 @@ pip-log.txt
 # Mac crap
 .DS_Store
 
-# Nuke build tool
-.nuke/temp
+# Fallout build tool
+.fallout/temp

AGENTS.md

@@ -0,0 +1,154 @@
+# AGENTS.md
+
+This guide helps coding agents become productive quickly in the AngleSharp.Css repository.
+
+## 1) What this repository is
+
+- AngleSharp.Css is the CSS extension package for AngleSharp.
+- It provides CSS parsing, CSSOM objects, declaration/value conversion, stylesheet integration, and render tree support.
+- Main code lives in `src/AngleSharp.Css`.
+- Tests live in `src/AngleSharp.Css.Tests`.
+
+## 2) Fast start commands
+
+From repository root:
+
+```bash
+# Full build + unit tests through Fallout (Linux/macOS)
+./build.sh
+
+# Full build + unit tests through Fallout (Windows PowerShell)
+./build.ps1
+
+# Run tests directly
+dotnet test src/AngleSharp.Css.Tests/AngleSharp.Css.Tests.csproj
+
+# Build solution directly
+dotnet build src/AngleSharp.Css.sln
+
+# Run CSS performance benchmark (Release)
+dotnet run --project src/AngleSharp.Performance.Css/AngleSharp.Performance.Css.csproj -c Release --framework net10.0
+
+# Short benchmark smoke run
+dotnet run --project src/AngleSharp.Performance.Css/AngleSharp.Performance.Css.csproj -c Release --framework net10.0 -- --job short
+```
+
+Notes:
+
+- CI invokes `./build.sh -AngleSharpVersion 1.5.0` on Linux and `./build.ps1` on Windows.
+- Treat warnings as errors is enabled in `src/Directory.Build.props`.
+
+## 3) Build and target framework facts
+
+- Library project: `src/AngleSharp.Css/AngleSharp.Css.csproj`
+  - Targets: `netstandard2.0;net8.0;net10.0`
+  - Additional Windows-only targets: `net462;net472`
+- Test project: `src/AngleSharp.Css.Tests/AngleSharp.Css.Tests.csproj`
+  - Targets: `net8.0`
+- Fallout entrypoint: `build/Build.cs`
+  - Default target chain runs unit tests.
+
+## 4) Repository map (where to change what)
+
+- `src/AngleSharp.Css/Parser`
+  - Front-end parser (`CssParser`), tokenizer, builder, and micro parsers.
+  - If parsing/tokenization behavior changes, start here.
+
+- `src/AngleSharp.Css/Declarations`
+  - One static class per declaration (name, converter, initial value, flags).
+  - Example pattern: `DisplayDeclaration.cs`.
+
+- `src/AngleSharp.Css/Factories/DefaultDeclarationFactory.cs`
+  - Central registration table that wires declaration metadata.
+  - New declaration support usually needs an entry here.
+
+- `src/AngleSharp.Css/ValueConverters.cs` and `src/AngleSharp.Css/Converters`
+  - Converter composition and reusable converter building blocks.
+  - New value grammar often starts with a converter addition or composition.
+
+- `src/AngleSharp.Css/Values`
+  - CSS value object model (primitives, composites, function values, tuples/lists).
+
+- `src/AngleSharp.Css/Dom` and `src/AngleSharp.Css/Dom/Internal`
+  - Public CSSOM interfaces/enums and internal implementations of rules, declarations, and sheets.
+
+- `src/AngleSharp.Css/Constants`
+  - Canonical names and keyword constants (`PropertyNames`, `RuleNames`, `CssKeywords`, etc.).
+
+- `src/AngleSharp.Css/RenderTree`
+  - Render tree construction and render node/value computation.
+
+- `src/AngleSharp.Css/FeatureValidators`
+  - Validators used for media feature / supports-style checks.
+
+- `src/AngleSharp.Css.Tests`
+  - Test suites grouped by concern: declarations, rules, parsing, values, styling, extensions.
+
+## 5) Common change playbooks
+
+### Add or adjust a CSS declaration/property
+
+1. Add or update declaration metadata class in `src/AngleSharp.Css/Declarations`.
+2. Ensure canonical property name exists in `src/AngleSharp.Css/Constants/PropertyNames.cs`.
+3. Wire declaration in `src/AngleSharp.Css/Factories/DefaultDeclarationFactory.cs`.
+4. Add tests in `src/AngleSharp.Css.Tests/Declarations` and/or related top-level declaration test files.
+5. Validate computed/style integration with tests in `src/AngleSharp.Css.Tests/Styling` when behavior impacts cascade/computation.
+
+### Add or adjust value grammar
+
+1. Extend converter composition in `src/AngleSharp.Css/ValueConverters.cs` and/or converter implementations in `src/AngleSharp.Css/Converters`.
+2. Add/update specific value objects in `src/AngleSharp.Css/Values` if needed.
+3. If grammar requires function or token-level parser support, update `src/AngleSharp.Css/Parser/Micro`.
+4. Add tests under `src/AngleSharp.Css.Tests/Values` and declaration tests that consume the grammar.
+
+### Add or adjust at-rules / CSSOM rule behavior
+
+1. Public contract changes in `src/AngleSharp.Css/Dom` interfaces.
+2. Implementation changes in `src/AngleSharp.Css/Dom/Internal/Rules`.
+3. Parser/builder adjustments in `src/AngleSharp.Css/Parser`.
+4. Rule-focused tests in `src/AngleSharp.Css.Tests/Rules`.
+
+### Render-tree-related changes
+
+1. Update computation/building in `src/AngleSharp.Css/RenderTree`.
+2. Confirm integration in `src/AngleSharp.Css/Extensions/WindowExtensions.cs` and styling flows.
+3. Add or update tests in `src/AngleSharp.Css.Tests/Styling`.
+
+## 6) Test strategy for agents
+
+- Prefer targeted test runs while iterating:
+
+```bash
+dotnet test src/AngleSharp.Css.Tests/AngleSharp.Css.Tests.csproj --filter FullyQualifiedName~CssProperty
+```
+
+- Before finishing, run full tests for confidence:
+
+```bash
+dotnet test src/AngleSharp.Css.Tests/AngleSharp.Css.Tests.csproj
+```
+
+- If changing multi-target-sensitive code (conditional behavior, APIs), also run full build via Fallout script to mimic CI flow.
+
+## 7) Style and safety expectations
+
+- Follow `.editorconfig` (spaces, indent size 4 for `.cs`, LF endings).
+- Preserve existing namespace/file organization; this repo is convention-heavy.
+- Avoid broad refactors when making focused feature fixes.
+- Keep public API changes intentional; many files under `Dom` are effectively surface area.
+- Existing code mixes nullable contexts (`#nullable enable` and `#nullable disable`); do not normalize unrelated files.
+- In `src/AngleSharp.Css/ValueConverters.cs`, avoid static field initializers that reference converters declared later in the same file. Forward references can capture `null` during type initialization and only fail at runtime.
+
+## 8) Documentation and onboarding references
+
+- Root overview: `README.md`
+- Extended docs index: `docs/README.md`
+- Suggested docs learning order is documented in `docs/README.md`.
+
+## 9) Quick pre-PR checklist for agents
+
+1. Did I update all required wiring points (constants, declaration metadata, factory registration, parser/converter where needed)?
+2. Did I add focused tests in the closest matching test area?
+3. Does `dotnet test src/AngleSharp.Css.Tests/AngleSharp.Css.Tests.csproj` pass?
+4. If CI-relevant build behavior changed, did I run `./build.sh` (or `./build.ps1` on Windows)?
+5. Did I avoid unrelated formatting churn and preserve established structure?

CHANGELOG.md

@@ -1,3 +1,10 @@
+# 1.0.1
+
+Released on Friday, July 31 2026.
+
+- Fixed NRE in `mask-image` with gradients (#218)
+- Improved cascade resolution performance (#220) @lahma
+
 # 1.0.0
 
 Released on Sunday, July 26 2026.

CLAUDE.md

@@ -0,0 +1,8 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+The guidance is shared with every AI agent working here, so it lives in AGENTS.md and is
+imported below. Record new guidance there rather than in this file.
+
+@AGENTS.md

build.ps1

@@ -13,10 +13,9 @@ $PSScriptRoot = Split-Path $MyInvocation.MyCommand.Path -Parent
 # CONFIGURATION
 ###########################################################################
 
-$BuildProjectFile = "$PSScriptRoot\nuke\_build.csproj"
-$TempDirectory = "$PSScriptRoot\\.nuke\temp"
+$TempDirectory = "$PSScriptRoot\.fallout\temp"
 
-$DotNetGlobalFile = "$PSScriptRoot\\global.json"
+$DotNetGlobalFile = "$PSScriptRoot\global.json"
 $DotNetInstallUrl = "https://dot.net/v1/dotnet-install.ps1"
 $DotNetChannel = "STS"
 
@@ -32,7 +31,7 @@ function ExecSafe([scriptblock] $cmd) {
     if ($LASTEXITCODE) { exit $LASTEXITCODE }
 }
 
-# If dotnet CLI is installed globally and it matches requested version, use for execution
+# If dotnet CLI is installed globally, use it; otherwise provision a local copy under .fallout\temp.
 if ($null -ne (Get-Command "dotnet" -ErrorAction SilentlyContinue) -and `
      $(dotnet --version) -and $LASTEXITCODE -eq 0) {
     $env:DOTNET_EXE = (Get-Command "dotnet").Path
@@ -65,10 +64,5 @@ else {
 
 Write-Output "Microsoft (R) .NET SDK version $(& $env:DOTNET_EXE --version)"
 
-if (Test-Path env:NUKE_ENTERPRISE_TOKEN) {
-    & $env:DOTNET_EXE nuget remove source "nuke-enterprise" > $null
-    & $env:DOTNET_EXE nuget add source "https://f.feedz.io/nuke/enterprise/nuget" --name "nuke-enterprise" --username "PAT" --password $env:NUKE_ENTERPRISE_TOKEN > $null
-}
-
-ExecSafe { & $env:DOTNET_EXE build $BuildProjectFile /nodeReuse:false /p:UseSharedCompilation=false -nologo -clp:NoSummary --verbosity quiet }
-ExecSafe { & $env:DOTNET_EXE run --project $BuildProjectFile --no-build -- $BuildArguments }
+ExecSafe { & $env:DOTNET_EXE tool restore }
+ExecSafe { & $env:DOTNET_EXE fallout $BuildArguments }

build.sh

@@ -9,10 +9,9 @@ SCRIPT_DIR=$(cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd)
 # CONFIGURATION
 ###########################################################################
 
-BUILD_PROJECT_FILE="$SCRIPT_DIR/nuke/_build.csproj"
-TEMP_DIRECTORY="$SCRIPT_DIR//.nuke/temp"
+TEMP_DIRECTORY="$SCRIPT_DIR/.fallout/temp"
 
-DOTNET_GLOBAL_FILE="$SCRIPT_DIR//global.json"
+DOTNET_GLOBAL_FILE="$SCRIPT_DIR/global.json"
 DOTNET_INSTALL_URL="https://dot.net/v1/dotnet-install.sh"
 DOTNET_CHANNEL="STS"
 
@@ -27,7 +26,7 @@ function FirstJsonValue {
     perl -nle 'print $1 if m{"'"$1"'": "([^"]+)",?}' <<< "${@:2}"
 }
 
-# If dotnet CLI is installed globally and it matches requested version, use for execution
+# If dotnet CLI is installed globally, use it; otherwise provision a local copy under .fallout/temp.
 if [ -x "$(command -v dotnet)" ] && dotnet --version &>/dev/null; then
     export DOTNET_EXE="$(command -v dotnet)"
 else
@@ -58,10 +57,5 @@ fi
 
 echo "Microsoft (R) .NET SDK version $("$DOTNET_EXE" --version)"
 
-if [[ ! -z ${NUKE_ENTERPRISE_TOKEN+x} && "$NUKE_ENTERPRISE_TOKEN" != "" ]]; then
-    "$DOTNET_EXE" nuget remove source "nuke-enterprise" &>/dev/null || true
-    "$DOTNET_EXE" nuget add source "https://f.feedz.io/nuke/enterprise/nuget" --name "nuke-enterprise" --username "PAT" --password "$NUKE_ENTERPRISE_TOKEN" --store-password-in-clear-text &>/dev/null || true
-fi
-
-"$DOTNET_EXE" build "$BUILD_PROJECT_FILE" /nodeReuse:false /p:UseSharedCompilation=false -nologo -clp:NoSummary --verbosity quiet
-"$DOTNET_EXE" run --project "$BUILD_PROJECT_FILE" --no-build -- "$@"
+"$DOTNET_EXE" tool restore
+exec "$DOTNET_EXE" fallout "$@"