No, sorry, that didn’t work either. I even tried combining both of your suggestions at the same time.
What else can I try?

Here’s what’s in the General Styling > Quick CSS box:

#top #header.header_color.av_header_transparency .av-main-nav > li > a .avia-menu-text {
color: white !important;
}
.home #avia-menu .avia-menu-fx {
color:white !important;
}
/*.post-entry > a:nth-child(1) > img:nth-child(1) {
height: 180px !important;
max-height: 180px !important;
width: auto !important;
}*/
#header_splash {
height: 360px !important;
}
#header_splash .av-section-color-overlay {
height: 360px !important;
}
.slide-entry-excerpt {
color: white;
text-align: center;
}