floating buttons problem display on dark background

First of all, thanks for this very practical and design module ! However, I am having a display problem.
I use the module without text associated with the icons.
On white background no display problem but on dark background, little gray lines appear instead of text
..... see in the attached pictures if I'm not clear

Thanks for your help
Martine

Hi the web site is under development... not yet published

perfect ! it works !!!! thank you very much for your response