.slider{
width:100%;
height:100px;
border:solid 0px #555;
padding:0;
position:relative;
margin:10px auto;
}

#slider-list{
list-style-type:none;
display:flex;
margin:0;
left:0;
top:0;
padding:0;
}

#slider-list img{
width:200px;
height:100px;
margin:0;
}

@keyframes slide{
0%{left:0px;}
10%{left:0px;}
35%{left:-100%;}
45%{left:-100%;}
75%{left:-200%;}
85%{left:-200%;}
90%{left:0px;}
}

#slid_list{
[...]
animation:slide 15s linear infinite;
}