Transparent hover on arrows not working

[mmolddelete]

Hi Daniel.

For some strange reason the left-right arrows on the plugin installation on my site become opaque (black) once hovering over them with the mouse (see attached). As troubleshooting I've reinstalled the plugin, commented out my CSS and also disabled the Koken CDN plugin (in case the icons were inaccesible). None of these have fixed the isse. Also, inspecting the element I cannot reproduce the issue. I'm also on your latest build of the plugin.

Do you know why this can be? It is observable on all my galleries, you can use this one if you happen to need to inspect the code http://marcosmontero.es/albums/turkey/

Many thanks in advance for your help.

Marcos