Resize background image like the site when changhe zoom in browser

[maxvel]

Hi, I have put background image on my Rolex page ex.:   http://www.privatecollections.it/it/en/rolex  but if I change the zoom of browser it will change dimensions not as the site. I have try to put codes  like background size..cover..fixed but it don't resize like the site. Here is the part of the code in global.css :....  . Someone can hel p me to have the bg image Always resized like the site also using zoom browser? thanks

/* Changes 03 march 2015 for Category by ID 4 */

 

 

 

body.category-rolex .columns-container {

 

  background: url(../img/bg-rolex-bureau-chiara-multi.jpg) 82% 0 no-repeat;

 

}

 

body.category-patek-philippe .columns-container {

 

  background: url(../img/bg-category-patek.jpg) 82% 0 no-repeat;

 

}

 

body.category-jaeger-lecoultre .columns-container {

 

  background: url(../img/bg-jaeger-chiara.jpg) 82% 0 no-repeat;

 

}

 

body.category-brands .columns-container {

  background: url(../img/brands1.jpg) 96% 0 no-repeat;