@oly: I see that you have added Custom CSS in “Appearance => Theme Options => Custom CSS” box. Can you try removing the following css from custom css box.
#main-slider .entry-title a,
#main-slider .entry-title span {
background: rgba(255, 255, 255, 0.7);
color: #222;
display: block;
padding: 15px 25px;
padding: 1.5rem 2.5rem;
}
#main-slider .entry-title a:hover,
#main-slider .entry-title span:hover,
#main-slider .entry-content:hover,
#slider-nav a:hover {
color: #000;
background: rgba(255, 255, 255, 1);
}