将以下代码放置于 style.php 文件中

<?php
header('Content-type: text/css');
ob_start("compress");
function compress($buffer)
{
    /* remove comments */
    $buffer = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $buffer);
    /* remove tabs, spaces, newlines, etc. */
    $buffer = str_replace(array("
", "\r", "\n", "\t", '  ', '    ', '    '), '', $buffer);
    return $buffer;
}
// 包含样式文件
include 'style.css';

ob_end_flush();

然后在 HTML 页面中在引入样式的地方引入该php文件：

<link rel="stylesheet" type="text/css" href="style.php"/>