4
colours are defined in your themes style.css file.
div.errorMsg { background-color: #FFCCCC; text-align: center; border-top: 1px solid #DDDDFF; border-left: 1px solid #DDDDFF; border-right: 1px solid #AAAAAA; border-bottom: 1px solid #AAAAAA; font-weight: bold; padding: 10px;}
div.confirmMsg { background-color: #DDFFDF; color: #136C99; text-align: center; border-top: 1px solid #DDDDFF; border-left: 1px solid #DDDDFF; border-right: 1px solid #AAAAAA; border-bottom: 1px solid #AAAAAA; font-weight: bold; padding: 10px;}
div.resultMsg { background-color : #CCCCCC; color: #333333; text-align: center; border-top: 1px solid silver; border-left: 1px solid silver; font-weight: bold; border-right: 1px solid #666666; border-bottom: 1px solid #666666; padding: 10px;}
the above is for the default template set, if you've cloned them and modified them like you have in your post above, then the above css classes will not work because you have removed the classes from the template.
as for how to edit templates and notice the changes, then read the FAQ section.
https://xoops.org/modules/smartfaq/category.php?categoryid=17