How can I set the margin for div reagent?


I'm new in css and write this code for that purpose:
want to achieve to this in resolution 1024:

screen: 1,024px
margins-left-right: 50px
columns: 58px
gutter: 12px

in my code can not set 50px margin for screen left and right ,how can i solve this problem?thanks all.
for more explain div col-1 margin left col-3 menu and margin right from screen.

You can use media query to set different css rules for different screen sizes. Please refer following links.