Category is un-clickable

I dont know why I can not click on the link in my category widget. I chekc my website, there is a <div class"petal"> above the area at the top of my website which prevents me from clicking the link. http://quynhinseoul.ypworks.vn/2015/04/28/goi-do-an-ve-tan-nha-kieu-han/

I fixed by this css
.no-slider .petal {
background: none;
display: none;
}