I think the test is complaining that your id for flex-flow does not correspond exactly to the header text for that section [line 101]. You could adjust the text and make sure it matches the id or remove " (Applies to: parent flex container element)" from the title (latter makes the test pass).
The last rule is complaining you have an extra
a class="nav-link" reference on line 231, removing the class from this link will pass the test. The test expects the number of
class="nav-link" to match the number of
class="main-section" in the document. This link doesn’t refer to a main-section.
Hope that helps