Do you have a browser extension that changes the colors or appearances of websites? If so, it is changing the color of your h1, which will cause the tests to fail.
Your code passes the tests for me. Please ensure your browser zoom is set to 100% and you have disabled any extensions that may interfere with FreeCodeCamp’s tests, such as dark mode. If these steps do not work, consider switching browsers. Chrome is the officially supported browser for the FreeCodeCamp curriculum.
You’ll want to turn off that extension for freeCodeCamp. We do have our own native “dark mode” that you can turn on in your account settings (the forum does too).