header-nav blocks user from clicking on navigation links

[jpikl]

It is caused by div with header-nav -expanded class which overlaps some of the top navigation links.

How to reproduce:

1. Open https://docpress.github.io
2. Open developer tools.
3. Switch to responsive mode.
4. Set device with to 500px.
5. Try to click on docpress link on top of the page.

I'm currently using this css as a workaround:

.header-nav.-expanded {
  pointer-events: none;
}
.header-nav.-expanded a {
  pointer-events: auto;
}