diff --git a/Pique.xcodeproj/project.pbxproj b/Pique.xcodeproj/project.pbxproj
index 4f98bfe..cc9dae0 100644
--- a/Pique.xcodeproj/project.pbxproj
+++ b/Pique.xcodeproj/project.pbxproj
@@ -22,6 +22,9 @@
 		A400000000000004 /* FormattingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D300000000000004 /* FormattingTests.swift */; };
 		A400000000000005 /* HTMLTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D300000000000005 /* HTMLTests.swift */; };
 		A400000000000006 /* HighlightIntegrationTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D300000000000006 /* HighlightIntegrationTests.swift */; };
+		A10000000000000B /* AppearanceSettings.swift in Sources */ = {isa = PBXBuildFile; fileRef = D10000000000000A /* AppearanceSettings.swift */; };
+		A20000000000000B /* AppearanceSettings.swift in Sources */ = {isa = PBXBuildFile; fileRef = D10000000000000A /* AppearanceSettings.swift */; };
+		A10000000000000C /* SettingsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D10000000000000B /* SettingsView.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -74,6 +77,8 @@
 		D300000000000004 /* FormattingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FormattingTests.swift; sourceTree = "<group>"; };
 		D300000000000005 /* HTMLTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HTMLTests.swift; sourceTree = "<group>"; };
 		D300000000000006 /* HighlightIntegrationTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HighlightIntegrationTests.swift; sourceTree = "<group>"; };
+		D10000000000000A /* AppearanceSettings.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppearanceSettings.swift; sourceTree = "<group>"; };
+		D10000000000000B /* SettingsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SettingsView.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -117,6 +122,7 @@
 			children = (
 				D100000000000001 /* PiqueApp.swift */,
 				D100000000000002 /* ContentView.swift */,
+				D10000000000000B /* SettingsView.swift */,
 				D100000000000003 /* Assets.xcassets */,
 				D100000000000004 /* Pique.entitlements */,
 			);
@@ -138,6 +144,7 @@
 			children = (
 				D100000000000008 /* SyntaxHighlighter.swift */,
 				D100000000000009 /* FileReader.swift */,
+				D10000000000000A /* AppearanceSettings.swift */,
 			);
 			path = Shared;
 			sourceTree = "<group>";
@@ -296,8 +303,10 @@
 			files = (
 				A100000000000001 /* PiqueApp.swift in Sources */,
 				A100000000000002 /* ContentView.swift in Sources */,
+				A10000000000000C /* SettingsView.swift in Sources */,
 				A100000000000005 /* SyntaxHighlighter.swift in Sources */,
 				A100000000000007 /* FileReader.swift in Sources */,
+				A10000000000000B /* AppearanceSettings.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -308,6 +317,7 @@
 				A200000000000004 /* PreviewProvider.swift in Sources */,
 				A200000000000006 /* SyntaxHighlighter.swift in Sources */,
 				A200000000000008 /* FileReader.swift in Sources */,
+				A20000000000000B /* AppearanceSettings.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/PiquePreview/Info.plist b/PiquePreview/Info.plist
index 12a260b..41fb62c 100644
--- a/PiquePreview/Info.plist
+++ b/PiquePreview/Info.plist
@@ -96,6 +96,24 @@
 					</array>
 				</dict>
 			</dict>
+			<dict>
+				<key>UTTypeIdentifier</key>
+				<string>io.macadmins.pique.ndjson</string>
+				<key>UTTypeDescription</key>
+				<string>Newline Delimited JSON</string>
+				<key>UTTypeConformsTo</key>
+				<array>
+					<string>public.plain-text</string>
+				</array>
+				<key>UTTypeTagSpecification</key>
+				<dict>
+					<key>public.filename-extension</key>
+					<array>
+						<string>ndjson</string>
+						<string>jsonl</string>
+					</array>
+				</dict>
+			</dict>
 		</array>
 		<key>NSExtension</key>
 		<dict>
@@ -106,6 +124,7 @@
 				<key>QLSupportedContentTypes</key>
 				<array>
 					<string>public.json</string>
+					<string>io.macadmins.pique.ndjson</string>
 					<string>public.yaml</string>
 					<string>public.xml</string>
 					<string>io.toml</string>
@@ -131,6 +150,8 @@
 				<key>QLFileExtensions</key>
 				<array>
 					<string>json</string>
+					<string>ndjson</string>
+					<string>jsonl</string>
 					<string>yaml</string>
 					<string>yml</string>
 					<string>toml</string>
diff --git a/PiquePreview/PreviewProvider.swift b/PiquePreview/PreviewProvider.swift
index 31ff4ec..bd6744f 100644
--- a/PiquePreview/PreviewProvider.swift
+++ b/PiquePreview/PreviewProvider.swift
@@ -92,7 +92,7 @@ class PreviewProvider: NSViewController, QLPreviewingController {
     /// Maps a file extension to a format group name matching AppearanceSettings keys.
     private static func formatName(for ext: String) -> String {
         switch ext.lowercased() {
-        case "json":                                              return "JSON"
+        case "json", "ndjson", "jsonl":                            return "JSON"
         case "yaml", "yml":                                      return "YAML"
         case "toml", "lock":                                     return "TOML"
         case "xml", "recipe":                                    return "XML"
diff --git a/PiqueTests/FileFormatTests.swift b/PiqueTests/FileFormatTests.swift
index 67d2acf..144746f 100644
--- a/PiqueTests/FileFormatTests.swift
+++ b/PiqueTests/FileFormatTests.swift
@@ -7,6 +7,8 @@ final class FileFormatTests: XCTestCase {
 
     func testJSON() {
         XCTAssertEqual(FileFormat(pathExtension: "json"), .json)
+        XCTAssertEqual(FileFormat(pathExtension: "ndjson"), .json)
+        XCTAssertEqual(FileFormat(pathExtension: "jsonl"), .json)
     }
 
     func testYAML() {
diff --git a/Shared/SyntaxHighlighter.swift b/Shared/SyntaxHighlighter.swift
index 352f184..84839d9 100644
--- a/Shared/SyntaxHighlighter.swift
+++ b/Shared/SyntaxHighlighter.swift
@@ -11,7 +11,7 @@ enum FileFormat {
 
     init?(pathExtension: String) {
         switch pathExtension.lowercased() {
-        case "json": self = .json
+        case "json", "ndjson", "jsonl": self = .json
         case "yaml", "yml": self = .yaml
         case "toml", "lock": self = .toml
         case "xml", "recipe": self = .xml