Currently, my shop page uses two main div tags for the sidebar and the main content area as follows
<div class="content main-products-loop col-md-9 col-md-push-3">
<div class="col-md-3 col-md-pull-9 sidebar sidebar-left sidebar-enabled">
I want to change this layout as follow
<div class="content main-products-loop col-md-10 col-md-push-2">
<div class="col-md-2 col-md-pull-10 sidebar sidebar-left sidebar-enabled ">
How and where can I apply this change without making any overrides to the original documents? I want to be able to have this change even after I update the theme files.