CSS for Results page

Search results: Store Locator Plus: If you’ve made a custom CSS file for the Results page and put it in the css folder for the plug-in, it gets knocked out when you update the plug-in (goes back to the default-css). Is there a way for that not to happen? Somewhere else I can put the CSS where it is “safe”?

http://ww.wp.xz.cn/plugins/store-locator-le/