function FlipTheCSSFile($css_file, $dir='RTL') {
        $css_data = file_get_contents($css_file);
        //remove comments 
        $css_data = preg_replace('/\/\*(.*)?\*\//Usi','' ,$css_data);
        //rewrite padding,margin 
        $css_data = preg_replace('/(\h*)(padding|margin):(.+)\h+(.+)\h+(.+)\h+(.+)\h*;/Ui',"\\1\\2-right:\\4;\\1\\2-left:\\5;" ,$css_data);
        //rewrite border-radius 
        $css_data = preg_replace('/(\h*|)border-radius:(.+)\h+(.+)\h+(.+)\h+(.+)\h*;/Ui',"\\1border-top-left-radius:\\2;\\1border-top-".
                    "right-radius:\\3;\\1border-bottom-right-radius:\\4;\\1border-bottom-left-radius:\\5;", $css_data);
        //start parsing css file
        $css_data = preg_replace('/(@media .+){(.+)}\s*}/Uis', '\1$\2}$', $css_data);
        preg_match_all('/(.+){(.+)(}\$|})/Uis', $css_data, $css_arr);
        $css_flipped    = "/* Created by flipcss.php 0.4 by daif alotaibi (http://daif.net) */\n\nbody{\n\tdirection:$dir;\n}\n\n";
        foreach($css_arr[0] as $key=>$val) {
            if(preg_match('/left|right/i', $css_arr[2][$key])) { // TODO: direction rule 
                if($rules = FlipTheCSSRules($css_arr[2][$key])) {
                    $css_flipped .= trim(str_replace('$','{',$css_arr[1][$key]));
                    $css_flipped .= " {\n\t".trim($rules)."\n";
                    $css_flipped .= str_replace('$',"\n}",$css_arr[3][$key])."\n\n";
                }
            }
        }
        file_put_contents(substr($css_file,0,-4).'-'.strtolower($dir).'.css', $css_flipped);
        print "CSS File $css_file has been flipped to $dir direction.<br />\n";
    }
    
    function FlipTheCSSRules($rules) {
        $return         = '';
        $rules_arr      = explode(";", $rules);
        foreach($rules_arr as $rule) {
            //ignore rules that doesn't need flipping
            if(preg_match('/(left|right)/i', $rule)) {
                //flip float
                if(preg_match('/float\h*:\h*(.+)/i', $rule, $rule_arr)) {
                    $rule = 'float: '.((trim($rule_arr[1])=='left')?'right':'left');
                    $return .="\t".trim($rule).";\n";
                
                //flip text-align
                } elseif(preg_match('/text-align\h*:\h*(.+)/i', $rule, $rule_arr)) {
                    $rule = 'text-align: '.((trim($rule_arr[1])=='left')?'right':'left');
                    $return .="\t".trim($rule).";\n";
                
                //flip padding, margin
                } elseif(preg_match('/(\*|)(margin|padding)-(left|right)\h*:\h*(.+)/i', $rule, $rule_arr)) {
                    $dir = ((trim($rule_arr[3])=='left')?'right':'left');
                    //reset direction rule
                    if((trim($rule_arr[3]) == 'left' && !preg_match('/'.trim($rule_arr[2]).'\-right/i', $rules)) || (trim($rule_arr[2]) == 'right' && !preg_match('/'.trim($rule_arr[2]).'\-left/i', $rules))) {
                        $rule = trim($rule_arr[1]).trim($rule_arr[2]).'-'.$rule_arr[3].": 0;\n\t";
                    } else {
                        $rule = '';
                    }
                    $rule .= trim($rule_arr[1]).trim($rule_arr[2]).'-'.$dir.': '.$rule_arr[4];
                    $return .="\t".trim($rule).";\n";
                
                //flip border-radius
                } elseif(preg_match('/border-(top|bottom)-(left|right)-radius\h*:\h*(.+)/i', $rule, $rule_arr)) {
                    $dir = ((trim($rule_arr[2])=='left')?'right':'left');
                    //reset direction rule
                    if((trim($rule_arr[2]) == 'left' && !preg_match('/'.trim($rule_arr[1]).'\-right/i', $rules)) || (trim($rule_arr[2]) == 'right' && !preg_match('/'.trim($rule_arr[1]).'\-left/i', $rules))) {
                        $rule = 'border-'.$rule_arr[1].'-'.$rule_arr[2].'-radius: 0;'."\n\t";
                    } else {
                        $rule = '';
                    }
                    //write new direction rule
                    $rule .= 'border-'.$rule_arr[1].'-'.$dir.'-radius: '.$rule_arr[3];
                    $return .="\t".trim($rule).";\n";
                
                //flip left, right
                } elseif(preg_match('/\h+(left|right)\h*:\h*(.+)/i', $rule, $rule_arr)) {
                    $dir = ((trim($rule_arr[1])=='left')?'right':'left');
                    //reset LTR rule
                    if((trim($rule_arr[1]) == 'left' && !preg_match('/\h+right\h*:/i', $rules)) || (trim($rule_arr[1]) == 'right' && !preg_match('/\h+left\h*:/i', $rules))) {
                        $rule = trim($rule_arr[1]).": auto;\n\t";
                    } else {
                        $rule = '';
                    }
                    $rule .= $dir.': '.$rule_arr[2];
                    $return .="\t".trim($rule).";\n";
                }
            }
        }
        return($return);
    }

طريقة الاستعمال

<?php
	FlipTheCSSFile('style.css', 'RTL');
?>