.slider {
    width: 100%;
    margin: auto;
    overflow: hidden;
    border-bottom: #1575e4 1px solid;
    border-top: #1575e4 1px solid;
}

.slider ul {
    display: flex;
    padding: 0;
    width: 200%;

    animation: cambio 10s infinite;
    animation-direction: alternate;
}

.slider li{
    width: 100%;
    list-style: none;
}

.slider img {
    width: 100%;
}

@keyframes cambio {
    0% {margin-left: 0;}
    45% {margin-left: 0;}

    50% {margin-left: -100%;}
    100% {margin-left: -100%;}
}