var isMac = (navigator.appVersion.indexOf("Mac") != -1);

if((navigator.appName == "Microsoft Internet Explorer") && (parseInt(navigator.appVersion) >= 4 ) &&! isMac){document.write('<link rel="stylesheet" href="css/ktac-styles.css" type="text/css">');}
else if ((navigator.appName == "Microsoft Internet Explorer") && (parseInt(navigator.appVersion) >= 4) && isMac){document.write('<link rel="stylesheet" href="css/ktac-styles.css" type="text/css"/>');}
else if ((navigator.appName == "Netscape") && (parseInt(navigator.appVersion) >= 5) && isMac){document.write('<link rel="stylesheet" href="css/ktac-styles.css" type="text/css"/>');}
else if ((navigator.appName == "Netscape") && (parseInt(navigator.appVersion) >= 5) &&! isMac){document.write('<link rel="stylesheet" href="css/ktac-styles.css" type="text/css"/>');}
else if ((navigator.appName == "Netscape") && (parseInt(navigator.appVersion) >= 4) && isMac){document.write('<link rel="stylesheet" href="css/ktac-styles.css" type="text/css"/>');}
else if ((navigator.appName == "Netscape") && (parseInt(navigator.appVersion) >= 4) &&! isMac){document.write('<link rel="stylesheet" href="css/ktac-styles.css" type="text/css"/>'); }