$re = '/\.-?[_a-zA-Z]+[_a-zA-Z0-9-]*\s*\{(.*?)}/m';
$str = '<body> <style type="text/css"> .csB51708B8{text-align:left;text-indent:0pt;margin:0pt 0pt 12pt 0pt;line-height:16.5pt} .csBBD4C4C1{color:#2B2E2F;background-color:transparent;font-family:\'Lucida Sans Unicode\';font-size:10.5pt;font-weight:normal;font-style:normal;} .csFC0FFCA7{text-align:left;margin:8pt 0pt 12pt 0pt;line-height:16.5pt;list-style-type:decimal;color:#2B2E2F;background-color:transparent;font-family:\'Lucida Sans Unicode\';font-size:10.5pt;font-weight:normal;font-style:normal} .csB4C51EC2{color:#2B2E2F;background-color:transparent;font-family:\'Lucida Sans Unicode\';font-size:10.5pt;font-weight:normal;font-style:normal;text-decoration: none;} .csC575EB8B{color:#0000FF;background-color:transparent;font-family:\'Lucida Sans Unicode\';font-size:10.5pt;font-weight:normal;font-style:normal;text-decoration: underline;} .cs67EAC646{text-align:left;margin:8pt 0pt 8pt 0pt;line-height:16.5pt;list-style-type:decimal;color:#2B2E2F;background-color:transparent;font-family:\'Lucida Sans Unicode\';font-size:10.5pt;font-weight:normal;font-style:normal} .cs896AFE57{text-align:left;text-indent:0pt;margin:0pt 0pt 0pt 0pt;line-height:16.5pt} .csE2621F37{text-align:left;text-indent:0pt;margin:11pt 0pt 11pt 0pt;line-height:16.5pt} .cs2654AE3A{text-align:left;text-indent:0pt;margin:0pt 0pt 0pt 0pt} .csC8F6D76{color:#000000;background-color:transparent;font-family:Calibri;font-size:11pt;font-weight:normal;font-style:normal;} .cs8D3F54E5{color:#000000;background-color:transparent;font-family:Verdana;font-size:8pt;font-weight:normal;font-style:normal;} </style> <p class="csB51708B8"><span class="csBBD4C4C1">
...
</body> ';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php