* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.slider {
    width: 100%;
    height: 600px;
    overflow: hidden;
}

.slider ul{
    display: flex;
    animation: cambio 20s infinite alternate linear;
    width: 400%;
}

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

.slider img {
    width: 100%;
    height: 100%;
}

@keyframes cambio{
    0%{margin-left: 0;}
    20%{margin-left: 0;}

    25%{margin-left: -100%;}
    45%{margin-left: -100%;}

    50%{margin-left: -200%;}
    70%{margin-left: -200%;}

    75%{margin-left: -300%;}
    100%{margin-left: -300%;}
}