Technical Documentation Page - Help

I need someone to help me pass the remaining three test of this responsive web design project (Technical Documentation Page). I will really appreciate it. Thank you.

The tests are as follows;
12. Each element with the class of “nav-link” should contain text that corresponds to the text within each (e.g. if you have a “Hello world” section/header, your navbar should have an element which contains the text “Hello world”).
4. Each element with the class of “main-section” should also have an id that corresponds with the text of each contained within it. Any spaces should be replaced with underscores (e.g. The that contains the header “Javascript and Java” should have a corresponding id=“Javascript_and_Java”).
3. The first element within each .main-section should be a element which contains text that describes the topic of that section.

Please help out. Thank you.

Find below link to my project.

Hello ^^
I tried it on Firefox and it works once you correct the errors. Which one you find difficult to solve?

I have not been able to pass only test 4 and 12.

I am done with the project now. All tests are passing now.