Not at the moment, but it’s on our hitlist to revisit along with an improved Theme / Style system.
In the meantime, if you are viewing the dashboards on an Android/Fire tablet running Fully Kiosk Browser, you could use the trick in the following thread to inject custom CSS:
I think it would end up being something like:
let css = document.createElement('style');
css.type = 'text/css';
css.appendChild(document.createTextNode(".tile{color:black}"));
document.getElementsByTagName("head")[0].appendChild(css);
The main part you would adjust is the third line which inserts the style. It’s basically saying to set the default (text / icon) color for the tile to black. You could use any browser compatible color including hex / rgb formats here.
Alternatively, if you wanted to target just the icons within the tile, you could change the third line to something like:
css.appendChild(document.createTextNode(".tile .icon{color:black}"));