How do I remove the 'Yellow Background' on the Welcome message for guests???

[watty005]

Thanks for the reply Mark, I'm still having problem changing the background. I did what you said and found this

notices {
background: {vb:stylevar body_background.backgroundColor};
margin-bottom: {vb:math {vb:stylevar padding}/2};
}

.notices li {
background: {vb:stylevar notices_background};
font-size: {vb:math {vb:stylevar font.fontSize}-1}px;
color: {vb:stylevar body_color};
padding:{vb:math {vb:stylevar padding}/2} {vb:stylevar padding};
margin-bottom:{vb:math {vb:stylevar padding}/2};
-moz-box-shadow: -2px 2px 2px {vb:stylevar notices_shadow_color};
-webkit-box-shadow: -2px 2px 2px {vb:stylevar notices_shadow_color};
clear:both;
}

I need the background changed to white, What do I have to change to make this happen?