function includeCSS(p_file) {
	var v_css  = document.createElement('link');
	v_css.rel = 'stylesheet'
	v_css.type = 'text/css';
	v_css.href = "css/" + p_file;
	document.getElementsByTagName('head')[0].appendChild(v_css);
}

w = screen.width;
if(w>1920){
	includeCSS("riva2560.css");
}else if(w>1680){
	includeCSS("riva1920.css");
}else if(w>1440){
	includeCSS("riva1680.css");
}else if(w>1280){
	includeCSS("riva1440.css");
}else if(w>1024){
	includeCSS("riva1280.css");
}else{
	includeCSS("riva1024.css");
}