Hi there,
the Volume Site uses CSS – its in Customizer > Additional CSS – here are the two rules you need to change:
.slideout-header .slideout-exit {
color: #fff;
background-color: #ff3366;
}
.slideout-header .custom.slideout-toggle a {
background-color: #ff3366;
}
For reference the original Site includes posts documenting how to style and make changes to the volume site. You can reference them here:
https://gpsites.co/volume/how-to-change-the-custom-colors/