Change the actual colour of primaryLight to be something other than white.
Or change the colour of those elements by adding some code to EXTRA.css
.sidebar .section .primaryContent h3, .sidebar .section .primaryContent h3 a, .sidebar .section .secondaryContent h3, .sidebar .section .secondaryContent h3 a, .profilePage .mast .section.infoBlock h3 {
color: #000000;
}