@keyframes slidy {
  0% { left: 0%; }
16% { left: 0%; }
21% { left: -100%; }
37% { left: -100%; }
42% { left: -200%; }
58% { left: -200%; }
63% { left: -300%; }
79% { left: -300%; }
84% { left: -400%; }
100% { left: -400%; }
  }
  
  #cadres { width: 100%; float: left; }
  #slidercss { 
    overflow: hidden;
    display: flex;
    position: relative;
    width: 500%;
    margin: 0;
    left: 0;
    text-align: left;
    animation: 18s slidy alternate infinite; 
  }

  #slidercss2 { 
    overflow: hidden;
    display: flex;
    position: relative;
    width: 500%;
    margin: 0;
    left: 0;
    text-align: left;
    animation: 10s slidy alternate infinite; 
  }