@keyframes night1 {
    0% { opacity: 0; }
    25% { opacity: 0; }
    50% { opacity: 1; }
    75% { opacity: 1; }
    100% { opacity: 0; }
}
@-webkit-keyframes night1 {
    0% { opacity: 0; }
    25% { opacity: 0; }
    50% { opacity: 1; }
    75% { opacity: 1; }
    100% { opacity: 0; }
}
.night_slider {
    position: relative;
    top: 0;
    left: 0;
    width: 920px;
    height: 392px;
    overflow: hidden;
}
.night_slide {
    width: 920px;
    height: 392px;
    position: absolute;
    top: 0;
    left: 0;
}
.night_slide:nth-child(1) {
    animation: night1 30s linear infinite;
    -webkit-animation: night1 30s linear infinite;
}