Why is my nav not displaying all links as inline?

Why is my nav not displaying all links as inline?

My nav was displayed all nice and horizontal up until about 15 minutes
ago, when something I did apparently mucked everything up. Nothing I do
seems to help.
There is no set width to the nav, so there should be no reason for it to
force the last link below onto a second line. I tried assigning a class to
the last nav-anchor and then removed any "margin-right" there may have
been, but nothing. I couldn't identify any margins from other elements
that could influence it. But... when mousing over the nav in Chrome, the
freaking thing sometimes starts shaking around and then snapping into the
right place... all inline/horizontal on one line (until I click on a link,
then it just goes back).
I'm working locally, so the site isn't online.
Here's a link to the style.css: http://cdv.lt/Pu5 Here's a link to the
html: http://cdv.lt/Pu6