Heather Waterman

So you have the drop down box under your name and site actions and other places within your SharePoint site and you want to customize the colors or background a little.

Here is the CSS code from the CORE.CSS classes that you will want to change.  DO NOT MODIFY THE CORE.CSS

.ms-MenuUIPopupBody {
border:1px solid #868686;  
margin:0px; padding:0px; } 

.ms-MenuUIPopupBody TABLE {
color:#003399; 
font-size:100%; margin:0px; 
padding:0px;} 

.ms-MenuUIPopupBody div {cursor:pointer;} 

.ms-MenuUI, 
.ms-MenuUILarge, 
.ms-MenuUIRtL, 
.ms-MenuUILargeRtL {
background-color:#fafafa; 
background-repeat:repeat-y; cursor: pointer;} 

.ms-MenuUI, 
.ms-MenuUILarge {
background-position: left;} 

.ms-MenuUIRtL, 
.ms-MenuUILargeRtL {
background-position: right; } 

.ms-MenuUI {
background-image:url("/_layouts/images/MGrad.gif");} 

.ms-MenuUILarge {
background-image:url("/_layouts/images/MGradLarge.gif"); 
width:250px;} 

.ms-MenuUIRtL {
background-image:url("/_layouts/images/MGradRtl.gif");} 

.ms-MenuUILargeRtL {
background-image:url("/_layouts/images/MGradLargeRtl.gif"); 
width:250px;} 

.ms-MenuUIDisabled SPAN {color:#888888;} 

.ms-MenuUIItemTableCell, 
.ms-MenuUIItemTableCellCompact {
padding:2px; color:#003399; 
text-decoration:none; font-size:8pt; 
font-family:tahoma; } 

.ms-MenuUIItemTableCellCompact {
padding:1px 2px 1px 2px;} 

.ms-MenuUIItemTableCell A, 
.ms-MenuUIItemTableCellHover A, 
.ms-MenuUIItemTableCellCompact A, 
.ms-MenuUIItemTableCellCompactHover A {
color:#003399; text-decoration:none; } 

.ms-menuitemdescription {
color:#666666;} 

.ms-MenuUIItemTableCellHover, 
.ms-MenuUIItemTableCellCompactHover {
padding:1px; 
color:#003399; 
text-decoration:none; 
font-size:8pt; font-family:tahoma;} 

.ms-MenuUIItemTableCellCompactHover 
{padding:0px 1px 0px 1px;} 

.ms-MenuUIItemTableHover {
background-color:#ffe6a0; 
border:1px solid #d2b47a;} 

.ms-MenuUIItemTableHover .ms-menuitemdescription{
color:#333333;} 

.ms-MenuUIIcon, 
.ms-MenuUIIconRtL {
height:16px; width:24px;} 

.ms-MenuUIIconLarge, 
.ms-MenuUIIconLargeRtl {
height:16px; width:40px;} 

.ms-MenuUIIcon, 
.ms-MenuUIIconLarge {
padding:0px 6px 0px 2px;} 

.ms-MenuUIIconRtL, 
.ms-MenuUIIconLargeRtl {
padding:0px 2px 0px 6px;} 

.ms-MenuUILabel, 
.ms-MenuUILabelRtL, 
.ms-menuuilabelcompact, 
.ms-menuuilabelcompactRtl {width:100%;} 

.ms-MenuUILabel {
padding:2px 0px 3px 6px;} 

.ms-MenuUILabelRtL {
padding:2px 6px 3px 0px;} 

.ms-menuuilabelcompact {
padding:1px 0px 1px 7px;} 

.ms-menuuilabelcompactRtl {
padding:1px 7px 1px 0px;} 

.ms-MenuUISeparator, 
.ms-MenuUISeparatorRtL, 
.ms-MenuUISeparatorLarge, 
.ms-MenuUISeparatorLargeRtl {
background-color:#c5c5c5; 
font-size:1px; height:1px; line-height:1px;} 

.ms-MenuUISeparator {
margin:0px 0px 0px 32px;} 

.ms-MenuUISeparatorRtL {
margin:0px 32px 0px 0px;} 

.ms-MenuUISeparatorLarge {
margin:0px 0px 0px 48px;} 

.ms-MenuUISeparatorLargeRtl{
margin:0px 48px 0px 0px;}

Here are the final changes that I have come up with.  Use what items are applicable to you and leave the ones that you don't need to change.

.ms-MenuUIPopupBody {
border: 1px solid #333; margin: 0px; padding: 5px; 
background: #fff url('menuBG.jpg') no-repeat; 
color: #333;} 

.ms-MenuUIItemTableHover {
background: transparent; border: none;} 

.ms-MenuUISeparator, 
.ms-MenuUISeparatorRtL, 
.ms-MenuUISeparatorLarge, 
.ms-MenuUISeparatorLargeRtl {background: none;} 

.ms-MenuUILarge, 
.ms-MenuUIRtL, 
.ms-MenuUILargeRtL {background: transparent;} 

.ms-MenuUI {background: #transparent;} 

.ms-MenuUIItemTableCellHover, 
.ms-MenuUIItemTableCellHover a, 
.ms-MenuUIItemTableCellCompactHover, 
.ms-MenuUIItemTableCellCompactHover a {
color: #333; padding: 0px 10px 0 0px;} 

.ms-MenuUIItemTableCellCompact, 
.ms-MenuUIItemTableCellCompact a {
color: #999; padding: 0 10px  0 0;} 

.ms-MenuUIItemTableCell {
color: #999; padding: 0 10px 0 0px;}

The best way to see what class is being used is to use FireBug for FireFox.  It takes some digging to figure out what controls elements in SharePoint. 

I have been able to change quite a bit with just CSS and keeping hands off of the master page.