<style type="text/css">
@import 'css/screen.css' screen and (min-width: 960px);
@import 'css/phone.css' screen and (max-width: 599px);
<style type="text/css">
@import 'css/screen.css' screen and (min-width: 960px);
@import 'css/phone.css' screen and (max-width: 599px);