After transferring the site from localhost (Denwer) to hosting, some of the styling is lost.

I am seeking help 

What should I do if, after deploying the site on the hosting, the corner rounding in the display of the carousel block does not work, styled with the views fluid grid module, in the class I described in the theme's CSS file for rounding the header block - the background and other elements are applied. However, this corner rounding function does not work?

viewing in IE 9

that is, everything is fine on localhost - but when opening the same link from the server in that browser - it doesn't work

I have been working with Drupal recently, I have no experience, I ask for advice on what can be checked

I cleared the cache, optimization is enabled

thank you