.cb-slideshow,
.cb-slideshow:after { 
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0px;
    left: 0px;
    z-index: 0; 
}
.cb-slideshow:after { 
    content: '';
    background: rgba(255,255,255,0.13); 
}
.cb-slideshow li span { 
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0px;
    left: 0px;
    color: transparent;
    background-size: cover;
    background-position: 50% 50%;
    background-repeat: none;
    opacity: 0;
    z-index: 0;
    -webkit-backface-visibility: hidden;
    -webkit-animation: imageAnimation 18s linear infinite 0s;
    -moz-animation: imageAnimation 18s linear infinite 0s;
    -o-animation: imageAnimation 18s linear infinite 0s;
    -ms-animation: imageAnimation 18s linear infinite 0s;
    animation: imageAnimation 18s linear infinite 0s; 
}
.cb-slideshow li:nth-child(1) span { 
    background-image: url(../images/fondo1.jpg);
}
.cb-slideshow li:nth-child(2) span { 
    background-image: url(../images/fondo2.jpg);
    -webkit-animation-delay: 6s;
    -moz-animation-delay: 6s;
    -o-animation-delay: 6s;
    -ms-animation-delay: 6s;
    animation-delay: 6s; 
}
.cb-slideshow li:nth-child(3) span { 
    background-image: url(../images/fondo3.jpg);
    -webkit-animation-delay: 12s;
    -moz-animation-delay: 12s;
    -o-animation-delay: 12s;
    -ms-animation-delay: 12s;
    animation-delay: 12s; 
}
.cb-slideshow li:nth-child(4) span { 
    background-image: url(../images/fondo4.jpg);
    -webkit-animation-delay: 18s;
    -moz-animation-delay: 18s;
    -o-animation-delay: 18s;
    -ms-animation-delay: 18s;
    animation-delay: 18s; 
}
/* Animation for the slideshow images */
@-webkit-keyframes imageAnimation { 
    0% { opacity: 0;
        -webkit-animation-timing-function: ease-out; }
    8% { opacity: 1; }
    17% { opacity: 1; }
    60% { opacity: 0; }
    100% { opacity: 0; 
        -webkit-animation-timing-function: ease-in;}
}
/* Show at least something when animations not supported */
.no-cssanimations .cb-slideshow li span{
    opacity: 1;
}