#slidert{
    width: 95%;
    margin: auto;
    overflow: hidden;
}

#slidert ul {
    padding: 0px;
    display: flex;
    width: 400%;
    
    
    animation: cambio 20s infinite;
    animation-direction: alternate;
    
    
}

#slidert li {
    list-style: none;
    width: 100%;
}

#slidert img {
    width: 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%;} 
    
}