<?php
if ($kalan >= 31)
{
echo $kalan;
}
else if($kalan <= 10)
{ 
echo "<span style=\"color: #FF0000\">".$kalan."</span>";
}
else if($kalan <= 20)
{
echo "<span style=\"color: #FF6600\">".$kalan."</span>";
}
else if($kalan <= 30)
{
echo "<span style=\"color: #FFCC00\">".$kalan."</span>";
}

?>