At some point in the not-too-distant past, an update was made to many of the v2 public NationBuilder themes so that donate pages would appear differently in the site navigation. This is great because it draws more attention to those pages and hopefully increases the likelihood of a site visitor to donate on the website. However, for some of the Themes/Styles, the font color that is used for the contribute buttons is the same as the background color, making the button seem invisible and thus defeating the purpose of changing the color. For example, the green version of Verve causes the donate button to be invisible in the mobile nav on a tablet.
The red (default) version of Verve does not make it the same exact color, but the text color is a slightly darker shade of red than the background, so it is still hard to read.
Customer site (green):
Verve demo site (red):
Thanks for letting us know Brian. It looks like it's specifically happening at 766-767px. We'll deploy a fix for this promptly.