Your page looks good @fdozza. The test suite passes and the page is responsive.
Something to think about and possibly revisit. This is a suggestion.
Right now when viewed on a small screen the navbar remains on the right and the body of the doc becomes narrow.
It could be a little wider to take up some additional width in the container.
One other thing to think about is on smaller screens have the navbar at the top and then the body of the doc has more room to display and will be easier to read. Gives a better UX.
If you’re concerned about the user story failing when the screen is narrow it’s not an issue. Read the user story carefully. It states;
“On regular sized devices (laptops, desktops), the element with
id="navbar" should be shown on the left side of the screen and should always be visible to the user.” A narrow screen, simulating a handheld device is not a regular sized device.