function getCSS()
{
 datetoday = new Date();
 timenow=datetoday.getTime();
 datetoday.setTime(timenow);
 thehour = datetoday.getHours();

 if (thehour > 18)
  display = "/css/yoru.css";
 else if (thehour > 6)
  display = "/css/hiru.css";
 else if (thehour > 0)
  display = "/css/yoru.css";
 else
  display = "/css/yoru.css";
 var css = '<';  css+='link rel="stylesheet" href=' + display + ' \/';  css+='>';
 document.write(css);
// End -->
}

getCSS();