Options are appearing vertically?

I checked and according to me everything is all right. “Today, week, month, all” these options which should appear horizontally are in vertically at my site.

Can i have some help, please!

site is: http://www.entrancesofindia.com/jee-main-counselling-dates/

https://ww.wp.xz.cn/plugins/popular-posts-tab-widget-for-jetpack/