/*-------------------------------------------------------------------*/
/*                              Messages                             */
/*-------------------------------------------------------------------*/
div.messages { font-weight: bold; margin-bottom: 1.5em; padding: 10px 10px 10px 52px; }
#help { font-size: 0.9em; margin-bottom: 1em; }
.status { color: #264409; background: #E6EFC2 url("images/large-info.png") no-repeat 12px center; border: 1px solid #C6D880; padding: 5px 10px; }
div.error { background: #FBE3E4 url("images/large-stop.png") no-repeat 12px center; }
div.notice { color: #514721; background: #FFF6BF url("images/large-info.png") no-repeat 12px center; border-color: #FFD324; }
div.warning, tr.warning { border: 1px solid #F0C020; background: #FFFFDD url("images/large-alert.png") no-repeat 12px center; margin: 0 0 1em; padding: 1em 0 1em 5em; }
.error a { color: #8a1f11; text-decoration: underline; }
.notice a { color: #514721; text-decoration: underline; }
.success a { color: #264409; text-decoration: underline; }
span.admin-disabled { color: #DC1000; }
div.messages.success { color: #55872E; background: #F1F8EB; border: 1px solid #7AC142; }
div.messages ul { margin-bottom: 0; }
div.node .unpublished, div.comment .unpublished { font: bold 2em Arial, Helvetica, sans-serif; text-align: left; color: #FFCCCC; background: #FFF4F4 url("images/large-alert.png") no-repeat 12px center; padding: 5px 0 5px 52px; margin: 5px 0; border: none; }

Drupal Messages with a nice green color

Drupal Green Messages

drupal

CSS