pix_b = screen.height;
if (pix_b<600) document.write("<LINK href='data/styl4.css' REL='stylesheet' TYPE='text/css'>"); 
if (pix_b>599 && pix_b<768) document.write("<LINK href='data/styl6.css' REL='stylesheet' TYPE='text/css'>");
if (pix_b>767 && pix_b<1024) document.write("<LINK href='data/styl7.css' REL='stylesheet' TYPE='text/css'>");
if (pix_b>1023) document.write("<LINK href='data/styl9.css' REL='stylesheet' TYPE='text/css'>");