The header (above) should have an h1 and an h2. The h1 has been thrown waaaaay to the right, such that I can’t reach it via the scrollbar.
Furthermore, if you remove the justify-content from the header element, both heading elements will disappear, as will the horizontal scrollbar. If it’s set to center, the h1 will appear and the h2 will disappear.
If the writing-mode is set to be horizontal value, both headings will appear as expected.