Layerslider with a grey line

Dear Kriesi team,
In the layerslider that appears in the page http://corpopromo.com/en/methodology/ just before the text “Consultancy firm in Development of Web Communication Strategy” it appears a grey line I want to erase (I don’t want neither to appear a grey line below the same slider area).
For your information I enclose all the pieces of CSS code I am using and have included. I think is the third code for this item.

#after_layer_slider_1:before {
content: “”;
height: 5px;
width: 100%;
background: white;
display: block;
position: absolute;
top: -4px;
z-index: 100;
}

@media only screen and (max-width: 767px) {
.responsive #header .sub_menu, .responsive #header_meta .sub_menu>ul {
float: left; }}

.container_wrap {
border-top-width: 0 !important;
}

Many thanks and regards from Madrid, Adolfo