Hi,
There is a bug with search box, I experience this on official Shapely demo page as well but it’s easier to see on my site with larger header. My site -> http://animmal.studio/
If you move mouse above Press, Blog, About links on my site,(Area marked with red in this pic Imgur: The magic of the Internet) the search bar starts to appear/disappear and stutter.
I tried both Firefox and Chrome.