I get it occasionally (very rare actually) and it is not specific to any one site. I have had that happen here too. It is, at least in my case, a response time issue where the page gets served but the CSS does not. A simple reload fixes it as Mouser said above. Most often, I see this on high latency sites where the computer waits the allotted time and only receives part of the page, or if I stop it mid-load. It also seems to occur more often on sites with JavaScript thought I don't know why that would be - more code to load I would guess. Poor scripts? I don't know. One question I did have though, can't you set up the site to just serve the page and all packages including the JavaScript, THEN load it to run locally on the machine instead of running everything inline? Maybe I am a bit naive about this, but it seems like that might be the way to go for many reasons.