Hi,
the easy way is to add some custom code to adjust the width on the container element on larger screens.
See this tread for more information: http://forum.webflow.com/t/activate-1200px-large-screen-media-query/611
<style type="text/css">
@media screen and (min-width: 1200px) {
.w-container {
max-width: 1170px;
}
}
</style>