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diff --git a/Hutch/Views/Repositories/SyntaxHighlighter.swift b/Hutch/Views/Repositories/SyntaxHighlighter.swift
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+++ b/Hutch/Views/Repositories/SyntaxHighlighter.swift
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+import Foundation
+import Highlightr
+import SwiftUI
+import UIKit
+
+enum SyntaxHighlightTheme {
+    case light
+    case dark
+
+    init(userInterfaceStyle: UIUserInterfaceStyle) {
+        self = userInterfaceStyle == .dark ? .dark : .light
+    }
+
+    init(colorScheme: ColorScheme) {
+        self = colorScheme == .dark ? .dark : .light
+    }
+
+    /// highlight.js theme names bundled with Highlightr. Xcode-like in light,
+    /// a muted dark palette in dark, so highlighting reads as native on both.
+    var highlightrName: String {
+        switch self {
+        case .light: "xcode"
+        case .dark: "atom-one-dark"
+        }
+    }
+}
+
+/// Multi-language syntax highlighting backed by Highlightr (highlight.js).
+///
+/// Highlightr wraps a JavaScriptCore context and is not thread-safe, so each
+/// instance must stay on the thread/task that created it. Callers that fail to
+/// resolve a language — or hit an unavailable engine — get `nil` and should
+/// fall back to plain, escaped text.
+final class SyntaxHighlighter {
+    private let highlightr: Highlightr?
+    private let supportedLanguages: Set<String>
+
+    init(theme: SyntaxHighlightTheme) {
+        let engine = Highlightr()
+        engine?.setTheme(to: theme.highlightrName)
+        highlightr = engine
+        supportedLanguages = Set(engine?.supportedLanguages() ?? [])
+    }
+
+    /// Full-document highlighted string, or `nil` when the language is unknown
+    /// or the engine is unavailable.
+    func attributedText(for code: String, language: String?, font: UIFont) -> NSAttributedString? {
+        guard let highlightr, let language = resolvedLanguage(language) else { return nil }
+        highlightr.theme.setCodeFont(font)
+        return highlightr.highlight(code, as: language, fastRender: true)
+    }
+
+    /// Inner HTML for a `<code>` element — color-styled `<span>`s — or `nil` to
+    /// fall back. Colors are inlined, so the caller must regenerate when the
+    /// theme changes.
+    func highlightedHTML(for code: String, language: String?) -> String? {
+        guard let attributed = attributedText(for: code, language: language, font: Self.htmlMeasurementFont) else {
+            return nil
+        }
+        return Self.html(from: attributed)
+    }
+
+    private static let htmlMeasurementFont = UIFont.monospacedSystemFont(ofSize: 12, weight: .regular)
+
+    private func resolvedLanguage(_ raw: String?) -> String? {
+        guard let trimmed = raw?.trimmingCharacters(in: .whitespacesAndNewlines).lowercased(),
+              !trimmed.isEmpty else {
+            return nil
+        }
+        let mapped = Self.languageAliases[trimmed] ?? trimmed
+        return supportedLanguages.contains(mapped) ? mapped : nil
+    }
+
+    /// Resolves a filename to a highlight.js language identifier, or `nil` when
+    /// there is no confident match (so we render plain rather than mis-highlight).
+    static func language(forFileName fileName: String) -> String? {
+        let base = (fileName as NSString).lastPathComponent.lowercased()
+        if let byName = fileNameLanguages[base] {
+            return byName
+        }
+        let ext = (fileName as NSString).pathExtension.lowercased()
+        guard !ext.isEmpty else { return nil }
+        return extensionLanguages[ext]
+    }
+
+    private static func html(from attributed: NSAttributedString) -> String {
+        var html = ""
+        let range = NSRange(location: 0, length: attributed.length)
+        attributed.enumerateAttribute(.foregroundColor, in: range, options: []) { value, subrange, _ in
+            let fragment = (attributed.string as NSString).substring(with: subrange)
+            let escaped = escapeHTML(fragment)
+            if let color = value as? UIColor, let hex = color.hexRGBString {
+                html += "<span style=\"color:\(hex)\">\(escaped)</span>"
+            } else {
+                html += escaped
+            }
+        }
+        return html
+    }
+
+    /// Fence tags / short names that differ from highlight.js identifiers.
+    private static let languageAliases: [String: String] = [
+        "js": "javascript",
+        "jsx": "javascript",
+        "ts": "typescript",
+        "tsx": "typescript",
+        "py": "python",
+        "rb": "ruby",
+        "sh": "bash",
+        "shell": "bash",
+        "zsh": "bash",
+        "yml": "yaml",
+        "c++": "cpp",
+        "cc": "cpp",
+        "h": "cpp",
+        "hpp": "cpp",
+        "cs": "csharp",
+        "objc": "objectivec",
+        "objective-c": "objectivec",
+        "obj-c": "objectivec",
+        "html": "xml",
+        "htm": "xml",
+        "kt": "kotlin",
+        "rs": "rust",
+        "golang": "go",
+        "md": "markdown",
+        "ps1": "powershell",
+        "yaml": "yaml"
+    ]
+
+    /// Filenames without a useful extension.
+    private static let fileNameLanguages: [String: String] = [
+        "dockerfile": "dockerfile",
+        "makefile": "makefile",
+        "gnumakefile": "makefile",
+        "cmakelists.txt": "cmake",
+        "gemfile": "ruby",
+        "rakefile": "ruby",
+        "podfile": "ruby",
+        "package.swift": "swift"
+    ]
+
+    private static let extensionLanguages: [String: String] = [
+        "swift": "swift",
+        "js": "javascript",
+        "mjs": "javascript",
+        "cjs": "javascript",
+        "jsx": "javascript",
+        "ts": "typescript",
+        "tsx": "typescript",
+        "py": "python",
+        "rb": "ruby",
+        "go": "go",
+        "rs": "rust",
+        "c": "c",
+        "h": "c",
+        "cpp": "cpp",
+        "cxx": "cpp",
+        "cc": "cpp",
+        "hpp": "cpp",
+        "hxx": "cpp",
+        "m": "objectivec",
+        "mm": "objectivec",
+        "cs": "csharp",
+        "java": "java",
+        "kt": "kotlin",
+        "kts": "kotlin",
+        "scala": "scala",
+        "php": "php",
+        "pl": "perl",
+        "pm": "perl",
+        "lua": "lua",
+        "r": "r",
+        "dart": "dart",
+        "groovy": "groovy",
+        "hs": "haskell",
+        "ex": "elixir",
+        "exs": "elixir",
+        "erl": "erlang",
+        "clj": "clojure",
+        "sh": "bash",
+        "bash": "bash",
+        "zsh": "bash",
+        "fish": "bash",
+        "ps1": "powershell",
+        "json": "json",
+        "yaml": "yaml",
+        "yml": "yaml",
+        "toml": "ini",
+        "ini": "ini",
+        "cfg": "ini",
+        "conf": "ini",
+        "xml": "xml",
+        "html": "xml",
+        "htm": "xml",
+        "css": "css",
+        "scss": "scss",
+        "sass": "scss",
+        "less": "less",
+        "sql": "sql",
+        "md": "markdown",
+        "markdown": "markdown",
+        "diff": "diff",
+        "patch": "diff",
+        "cmake": "cmake",
+        "gradle": "groovy",
+        "vim": "vim"
+    ]
+}
+
+private extension UIColor {
+    /// `#rrggbb` for HTML inline styles, or `nil` if the color isn't RGB-convertible.
+    var hexRGBString: String? {
+        var red: CGFloat = 0
+        var green: CGFloat = 0
+        var blue: CGFloat = 0
+        var alpha: CGFloat = 0
+        guard getRed(&red, green: &green, blue: &blue, alpha: &alpha) else { return nil }
+        let clamp: (CGFloat) -> Int = { Int((max(0, min(1, $0)) * 255).rounded()) }
+        return String(format: "#%02x%02x%02x", clamp(red), clamp(green), clamp(blue))
+    }
+}