$(document).ready(function(){
   $('#categories_block_left .block_content li:first').children('a').css('color','#000000');
   $('#categories_block_left .block_content li:first').next().children('a').css('color','#000000');
   $('#categories_block_left .block_content li:first').next().next().children('a').css('color','#000000');
});