Automatically convert CSS file to be used on dark backgrounds

[divorced]

I have about 200 CSS files like this:\[code\]/** * GeSHi Dynamically Generated Stylesheet * -------------------------------------- * Dynamically generated stylesheet for bnf * CSS class: , CSS id: * GeSHi (C) 2004 - 2007 Nigel McNie, 2007 - 2008 Benny Baumann * (http://qbnz.com/highlighter/ and http://geshi.org/) * -------------------------------------- */.bnf .de1, .bnf .de2 {font: normal normal 1em/1.2em monospace; margin:0; padding:0; background:none; vertical-align:top;}.bnf {font-family:monospace;}.bnf .imp {font-weight: bold; color: red;}.bnf li, .bnf .li1 {font-weight: normal; vertical-align:top;}.bnf .ln {width:1px;text-align:right;margin:0;padding:0 2px;vertical-align:top;}.bnf .li2 {font-weight: bold; vertical-align:top;}.bnf .sy0 {color: #000066; font-weight: bold;}.bnf .st0 {color: #a00;}.bnf .st1 {color: #a00;}.bnf .re0 {color: #007;}.bnf .ln-xtra, .bnf li.ln-xtra, .bnf div.ln-xtra {background-color: #ffc;}.bnf span.xtra { display:block; }\[/code\]But colors in these CSS files are designed to look ok only on light (preferably white) backgrounds. Is there an algo (I can express in PHP code) I can apply to colors in these files to make them look nice on dark backgrounds (close to black)? May be I should just invert all colors? Or is there a better way?