diff --git a/.gitignore b/.gitignore
index 2861ad0..fa0476d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -48,9 +48,12 @@ build/
 # Test coverage files
 coverage.out
 coverage.txt
+coverage.html
+coverage.*
 coverage
 *.cover
 *.coverprofile
+main_coverage
 
 # Other common exclusions
 *.exe
diff --git a/README.md b/README.md
index 8b20f55..08679b4 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,16 @@
 
 A Go-based parser that converts Articulate Rise e-learning content to various formats including Markdown, HTML, and Word documents.
 
+[![Go version](https://img.shields.io/github/go-mod/go-version/kjanat/articulate-parser?logo=Go&logoColor=white)][gomod]
+[![Go Doc](https://godoc.org/github.com/kjanat/articulate-parser?status.svg)][Package documentation]
+[![Go Report Card](https://goreportcard.com/badge/github.com/kjanat/articulate-parser)][Go report]
+[![Tag](https://img.shields.io/github/v/tag/kjanat/articulate-parser?sort=semver&label=Tag)][Tags] <!-- [![Release Date](https://img.shields.io/github/release-date/kjanat/articulate-parser?label=Release%20date)][Latest release] -->
+[![License](https://img.shields.io/github/license/kjanat/articulate-parser?label=License)][MIT License] <!-- [![Commit activity](https://img.shields.io/github/commit-activity/m/kjanat/articulate-parser?label=Commit%20activity)][Commits] -->
+[![Last commit](https://img.shields.io/github/last-commit/kjanat/articulate-parser?label=Last%20commit)][Commits]
+[![GitHub Issues or Pull Requests](https://img.shields.io/github/issues/kjanat/articulate-parser?label=Issues)][Issues]
+[![CI](https://img.shields.io/github/actions/workflow/status/kjanat/articulate-parser/ci.yml?logo=github&label=CI)][Build]
+[![Codecov](https://img.shields.io/codecov/c/gh/kjanat/articulate-parser?token=eHhaHY8nut&logo=codecov&logoColor=%23F01F7A&label=Codecov)][Codecov]
+
 ## System Architecture
 
 ```mermaid
@@ -73,16 +83,6 @@ The system follows **Clean Architecture** principles with clear separation of co
 -   **📤 Export Layer**: Factory pattern for format-specific exporters
 -   **📊 Data Layer**: Domain models representing course structure
 
-[![Go version](https://img.shields.io/github/go-mod/go-version/kjanat/articulate-parser?logo=Go&logoColor=white)][gomod]
-[![Go Doc](https://godoc.org/github.com/kjanat/articulate-parser?status.svg)][Package documentation]
-[![Go Report Card](https://goreportcard.com/badge/github.com/kjanat/articulate-parser)][Go report]
-[![Tag](https://img.shields.io/github/v/tag/kjanat/articulate-parser?sort=semver&label=Tag)][Tags] <!-- [![Release Date](https://img.shields.io/github/release-date/kjanat/articulate-parser?label=Release%20date)][Latest release] -->
-[![License](https://img.shields.io/github/license/kjanat/articulate-parser?label=License)][MIT License] <!-- [![Commit activity](https://img.shields.io/github/commit-activity/m/kjanat/articulate-parser?label=Commit%20activity)][Commits] -->
-[![Last commit](https://img.shields.io/github/last-commit/kjanat/articulate-parser?label=Last%20commit)][Commits]
-[![GitHub Issues or Pull Requests](https://img.shields.io/github/issues/kjanat/articulate-parser?label=Issues)][Issues]
-[![CI](https://img.shields.io/github/actions/workflow/status/kjanat/articulate-parser/ci.yml?logo=github&label=CI)][Build]
-[![Codecov](https://img.shields.io/codecov/c/gh/kjanat/articulate-parser?token=eHhaHY8nut&logo=codecov&logoColor=%23F01F7A&label=Codecov)][Codecov]
-
 ## Features
 
 -   Parse Articulate Rise JSON data from URLs or local files
@@ -291,7 +291,7 @@ The parser includes error handling for:
 
 <!-- ## Code coverage
 
-![Sunburst](https://codecov.io/gh/kjanat/articulate-parser/graphs/tree.svg?token=eHhaHY8nut)
+![Sunburst](https://codecov.io/gh/kjanat/articulate-parser/graphs/sunburst.svg?token=eHhaHY8nut)
 
 ![Grid](https://codecov.io/gh/kjanat/articulate-parser/graphs/tree.svg?token=eHhaHY8nut)
 
@@ -315,12 +315,12 @@ The parser includes error handling for:
 
 Potential improvements could include:
 
--   PDF export support
--   Media file downloading
--   ~~HTML export with preserved styling~~ ✅ **Completed**
--   SCORM package support
--   Batch processing capabilities
--   Custom template support
+-   [ ]  PDF export support
+-   [ ]  Media file downloading
+-   [x]  ~~HTML export with preserved styling~~
+-   [ ]  SCORM package support
+-   [ ]  Batch processing capabilities
+-   [ ]  Custom template support
 
 ## License
 
diff --git a/internal/version/version.go b/internal/version/version.go
index 1280543..af6f20d 100644
--- a/internal/version/version.go
+++ b/internal/version/version.go
@@ -5,7 +5,7 @@ package version
 // Version information.
 var (
 	// Version is the current version of the application.
-	Version = "0.3.0"
+	Version = "0.3.1"
 
 	// BuildTime is the time the binary was built.
 	BuildTime = "unknown"
diff --git a/main.go b/main.go
index d2d873f..32156d4 100644
--- a/main.go
+++ b/main.go
@@ -16,6 +16,12 @@ import (
 // It handles command-line arguments, sets up dependencies,
 // and coordinates the parsing and exporting of courses.
 func main() {
+	os.Exit(run(os.Args))
+}
+
+// run contains the main application logic and returns an exit code.
+// This function is testable as it doesn't call os.Exit directly.
+func run(args []string) int {
 	// Dependency injection setup
 	htmlCleaner := services.NewHTMLCleaner()
 	parser := services.NewArticulateParser()
@@ -23,20 +29,20 @@ func main() {
 	app := services.NewApp(parser, exporterFactory)
 
 	// Check for required command-line arguments
-	if len(os.Args) < 4 {
-		fmt.Printf("Usage: %s <source> <format> <output>\n", os.Args[0])
+	if len(args) < 4 {
+		fmt.Printf("Usage: %s <source> <format> <output>\n", args[0])
 		fmt.Printf("  source: URI or file path to the course\n")
 		fmt.Printf("  format: export format (%s)\n", joinStrings(app.GetSupportedFormats(), ", "))
 		fmt.Printf("  output: output file path\n")
 		fmt.Println("\nExample:")
-		fmt.Printf("  %s articulate-sample.json markdown output.md\n", os.Args[0])
-		fmt.Printf("  %s https://rise.articulate.com/share/xyz docx output.docx\n", os.Args[0])
-		os.Exit(1)
+		fmt.Printf("  %s articulate-sample.json markdown output.md\n", args[0])
+		fmt.Printf("  %s https://rise.articulate.com/share/xyz docx output.docx\n", args[0])
+		return 1
 	}
 
-	source := os.Args[1]
-	format := os.Args[2]
-	output := os.Args[3]
+	source := args[1]
+	format := args[2]
+	output := args[3]
 
 	var err error
 
@@ -48,10 +54,12 @@ func main() {
 	}
 
 	if err != nil {
-		log.Fatalf("Error processing course: %v", err)
+		log.Printf("Error processing course: %v", err)
+		return 1
 	}
 
 	fmt.Printf("Successfully exported course to %s\n", output)
+	return 0
 }
 
 // isURI checks if a string is a URI by looking for http:// or https:// prefixes.
diff --git a/main_test.go b/main_test.go
index c982980..d776e2f 100644
--- a/main_test.go
+++ b/main_test.go
@@ -2,6 +2,12 @@
 package main
 
 import (
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strings"
 	"testing"
 )
 
@@ -173,3 +179,300 @@ func BenchmarkJoinStrings(b *testing.B) {
 		joinStrings(strs, separator)
 	}
 }
+
+// TestRunWithInsufficientArgs tests the run function with insufficient command-line arguments.
+func TestRunWithInsufficientArgs(t *testing.T) {
+	tests := []struct {
+		name string
+		args []string
+	}{
+		{
+			name: "no arguments",
+			args: []string{"articulate-parser"},
+		},
+		{
+			name: "one argument",
+			args: []string{"articulate-parser", "source"},
+		},
+		{
+			name: "two arguments",
+			args: []string{"articulate-parser", "source", "format"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Capture stdout
+			oldStdout := os.Stdout
+			r, w, _ := os.Pipe()
+			os.Stdout = w
+
+			// Run the function
+			exitCode := run(tt.args)
+
+			// Restore stdout
+			w.Close()
+			os.Stdout = oldStdout
+
+			// Read captured output
+			var buf bytes.Buffer
+			io.Copy(&buf, r)
+			output := buf.String()
+
+			// Verify exit code
+			if exitCode != 1 {
+				t.Errorf("Expected exit code 1, got %d", exitCode)
+			}
+
+			// Verify usage message is displayed
+			if !strings.Contains(output, "Usage:") {
+				t.Errorf("Expected usage message in output, got: %s", output)
+			}
+
+			if !strings.Contains(output, "export format") {
+				t.Errorf("Expected format information in output, got: %s", output)
+			}
+		})
+	}
+}
+
+// TestRunWithInvalidFile tests the run function with a non-existent file.
+func TestRunWithInvalidFile(t *testing.T) {
+	// Capture stdout and stderr
+	oldStdout := os.Stdout
+	oldStderr := os.Stderr
+	
+	stdoutR, stdoutW, _ := os.Pipe()
+	stderrR, stderrW, _ := os.Pipe()
+	
+	os.Stdout = stdoutW
+	os.Stderr = stderrW
+
+	// Also need to redirect log output
+	oldLogOutput := log.Writer()
+	log.SetOutput(stderrW)
+
+	// Run with non-existent file
+	args := []string{"articulate-parser", "nonexistent-file.json", "markdown", "output.md"}
+	exitCode := run(args)
+
+	// Restore stdout/stderr and log output
+	stdoutW.Close()
+	stderrW.Close()
+	os.Stdout = oldStdout
+	os.Stderr = oldStderr
+	log.SetOutput(oldLogOutput)
+
+	// Read captured output
+	var stdoutBuf, stderrBuf bytes.Buffer
+	io.Copy(&stdoutBuf, stdoutR)
+	io.Copy(&stderrBuf, stderrR)
+	
+	stdoutR.Close()
+	stderrR.Close()
+
+	// Verify exit code
+	if exitCode != 1 {
+		t.Errorf("Expected exit code 1 for non-existent file, got %d", exitCode)
+	}
+
+	// Should have error output
+	errorOutput := stderrBuf.String()
+	if !strings.Contains(errorOutput, "Error processing course") {
+		t.Errorf("Expected error message about processing course, got: %s", errorOutput)
+	}
+}
+
+// TestRunWithInvalidURI tests the run function with an invalid URI.
+func TestRunWithInvalidURI(t *testing.T) {
+	// Capture stdout and stderr
+	oldStdout := os.Stdout
+	oldStderr := os.Stderr
+	
+	stdoutR, stdoutW, _ := os.Pipe()
+	stderrR, stderrW, _ := os.Pipe()
+	
+	os.Stdout = stdoutW
+	os.Stderr = stderrW
+
+	// Also need to redirect log output
+	oldLogOutput := log.Writer()
+	log.SetOutput(stderrW)
+
+	// Run with invalid URI (will fail because we can't actually fetch)
+	args := []string{"articulate-parser", "https://example.com/invalid", "markdown", "output.md"}
+	exitCode := run(args)
+
+	// Restore stdout/stderr and log output
+	stdoutW.Close()
+	stderrW.Close()
+	os.Stdout = oldStdout
+	os.Stderr = oldStderr
+	log.SetOutput(oldLogOutput)
+
+	// Read captured output
+	var stdoutBuf, stderrBuf bytes.Buffer
+	io.Copy(&stdoutBuf, stdoutR)
+	io.Copy(&stderrBuf, stderrR)
+	
+	stdoutR.Close()
+	stderrR.Close()
+
+	// Should fail because the URI is invalid/unreachable
+	if exitCode != 1 {
+		t.Errorf("Expected failure (exit code 1) for invalid URI, got %d", exitCode)
+	}
+
+	// Should have error output
+	errorOutput := stderrBuf.String()
+	if !strings.Contains(errorOutput, "Error processing course") {
+		t.Errorf("Expected error message about processing course, got: %s", errorOutput)
+	}
+}
+
+// TestRunWithValidJSONFile tests the run function with a valid JSON file.
+func TestRunWithValidJSONFile(t *testing.T) {
+	// Create a temporary test JSON file
+	testContent := `{
+		"title": "Test Course",
+		"lessons": [
+			{
+				"id": "lesson1",
+				"title": "Test Lesson",
+				"blocks": [
+					{
+						"type": "text",
+						"id": "block1",
+						"data": {
+							"text": "Test content"
+						}
+					}
+				]
+			}
+		]
+	}`
+
+	tmpFile, err := os.CreateTemp("", "test-course-*.json")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	if _, err := tmpFile.WriteString(testContent); err != nil {
+		t.Fatalf("Failed to write test content: %v", err)
+	}
+	tmpFile.Close()
+
+	// Test successful run with valid file
+	outputFile := "test-output.md"
+	defer os.Remove(outputFile)
+
+	// Save original stdout
+	originalStdout := os.Stdout
+	defer func() { os.Stdout = originalStdout }()
+
+	// Capture stdout
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+
+	args := []string{"articulate-parser", tmpFile.Name(), "markdown", outputFile}
+	exitCode := run(args)
+
+	// Close write end and restore stdout
+	w.Close()
+	os.Stdout = originalStdout
+
+	// Read captured output
+	var buf bytes.Buffer
+	io.Copy(&buf, r)
+	output := buf.String()
+
+	// Verify successful execution
+	if exitCode != 0 {
+		t.Errorf("Expected successful execution (exit code 0), got %d", exitCode)
+	}
+
+	// Verify success message
+	expectedMsg := fmt.Sprintf("Successfully exported course to %s", outputFile)
+	if !strings.Contains(output, expectedMsg) {
+		t.Errorf("Expected success message '%s' in output, got: %s", expectedMsg, output)
+	}
+
+	// Verify output file was created
+	if _, err := os.Stat(outputFile); os.IsNotExist(err) {
+		t.Errorf("Expected output file %s to be created", outputFile)
+	}
+}
+
+// TestRunIntegration tests the run function with different output formats using sample file.
+func TestRunIntegration(t *testing.T) {
+	// Skip if sample file doesn't exist
+	if _, err := os.Stat("articulate-sample.json"); os.IsNotExist(err) {
+		t.Skip("Skipping integration test: articulate-sample.json not found")
+	}
+
+	formats := []struct {
+		format string
+		output string
+	}{
+		{"markdown", "test-output.md"},
+		{"html", "test-output.html"},
+		{"docx", "test-output.docx"},
+	}
+
+	for _, format := range formats {
+		t.Run("format_"+format.format, func(t *testing.T) {
+			// Capture stdout
+			oldStdout := os.Stdout
+			r, w, _ := os.Pipe()
+			os.Stdout = w
+
+			// Run the function
+			args := []string{"articulate-parser", "articulate-sample.json", format.format, format.output}
+			exitCode := run(args)
+
+			// Restore stdout
+			w.Close()
+			os.Stdout = oldStdout
+
+			// Read captured output
+			var buf bytes.Buffer
+			io.Copy(&buf, r)
+			output := buf.String()
+
+			// Clean up test file
+			defer os.Remove(format.output)
+
+			// Verify successful execution
+			if exitCode != 0 {
+				t.Errorf("Expected successful execution (exit code 0), got %d", exitCode)
+			}
+
+			// Verify success message
+			expectedMsg := "Successfully exported course to " + format.output
+			if !strings.Contains(output, expectedMsg) {
+				t.Errorf("Expected success message '%s' in output, got: %s", expectedMsg, output)
+			}
+
+			// Verify output file was created
+			if _, err := os.Stat(format.output); os.IsNotExist(err) {
+				t.Errorf("Expected output file %s to be created", format.output)
+			}
+		})
+	}
+}
+
+// TestMainFunction tests that the main function exists and is properly structured.
+// We can't test os.Exit behavior directly, but we can verify the main function
+// calls the run function correctly by testing run function behavior.
+func TestMainFunction(t *testing.T) {
+	// Test that insufficient args return exit code 1
+	exitCode := run([]string{"program"})
+	if exitCode != 1 {
+		t.Errorf("Expected run to return exit code 1 for insufficient args, got %d", exitCode)
+	}
+
+	// Test that main function exists (this is mainly for coverage)
+	// The main function just calls os.Exit(run(os.Args)), which we can't test directly
+	// but we've tested the run function thoroughly above.
+}