Slider Read-More Button does not show on mobile devices

The read more button from my slider is not showing on mobile devices. Therefore, no one can click through from a mobile device.

I tried the following Additional CSS code as found in the forum, but there was no success.

@media screen and (max-width: 420px){
#featured-slider .slider-read-more-button {
display: block; {
}
}

The page I need help with: [log in to see the link]