How do you integrate ExtentReports with Selenium and TestNG?

<dependency>
    <groupId>com.aventstack</groupId>
    <artifactId>extentreports</artifactId>
    <version>5.1.1</version>
</dependency>

public class ExtentReportManager {
    private static ExtentReports extent;
    private static ThreadLocal<ExtentTest> extentTest = new ThreadLocal<>();

    public static ExtentReports getInstance() {
        if (extent == null) {
            String reportPath = System.getProperty("user.dir") +
                                "/test-output/ExtentReport.html";
            ExtentSparkReporter spark = new ExtentSparkReporter(reportPath);
            spark.config().setDocumentTitle("AutomateQA Test Report");
            spark.config().setReportName("Regression Suite");
            spark.config().setTheme(Theme.DARK);

            extent = new ExtentReports();
            extent.attachReporter(spark);
            extent.setSystemInfo("OS", System.getProperty("os.name"));
            extent.setSystemInfo("Environment", "Staging");
            extent.setSystemInfo("Tester", "AutomateQA Team");
        }
        return extent;
    }

    public static void setTest(ExtentTest test) { extentTest.set(test); }
    public static ExtentTest getTest()          { return extentTest.get(); }
}

public class ExtentReportListener implements ITestListener {

    @Override
    public void onStart(ITestContext context) {
        ExtentReportManager.getInstance();
    }

    @Override
    public void onTestStart(ITestResult result) {
        ExtentTest test = ExtentReportManager.getInstance()
            .createTest(result.getMethod().getMethodName());
        ExtentReportManager.setTest(test);
        ExtentReportManager.getTest().info("Test started: " + result.getMethod().getMethodName());
    }

    @Override
    public void onTestSuccess(ITestResult result) {
        ExtentReportManager.getTest().pass("Test PASSED");
    }

    @Override
    public void onTestFailure(ITestResult result) {
        ExtentReportManager.getTest().fail(result.getThrowable());

        // Attach screenshot on failure
        try {
            WebDriver driver = DriverManager.getDriver();
            String base64 = ((TakesScreenshot) driver).getScreenshotAs(OutputType.BASE64);
            ExtentReportManager.getTest()
                .addScreenCaptureFromBase64String(base64, "Failure Screenshot");
        } catch (Exception e) {
            ExtentReportManager.getTest().warning("Could not capture screenshot: " + e.getMessage());
        }
    }

    @Override
    public void onTestSkipped(ITestResult result) {
        ExtentReportManager.getTest().skip(result.getThrowable());
    }

    @Override
    public void onFinish(ITestContext context) {
        ExtentReportManager.getInstance().flush(); // CRITICAL — writes report to disk
    }
}

<suite name="Regression">
    <listeners>
        <listener class-name="listeners.ExtentReportListener"/>
    </listeners>
    <test name="AllTests">
        <classes>
            <class name="tests.LoginTest"/>
        </classes>
    </test>
</suite>

@Test
public void loginTest() {
    ExtentReportManager.getTest().info("Navigating to login page");
    driver.findElement(By.id("username")).sendKeys("admin");

    ExtentReportManager.getTest().info("Entering credentials");
    driver.findElement(By.id("password")).sendKeys("secret");
    driver.findElement(By.id("loginBtn")).click();

    Assert.assertTrue(driver.getTitle().contains("Dashboard"));
    ExtentReportManager.getTest().pass("Login successful — dashboard loaded");
}