.foot-print-container {position:relative; width:220px; margin:5px auto 0 auto; border:0px solid purple;}

/* position and animate */
    
.foot-print-1 {
  opacity:0;
  position:absolute;
  left:10px;
  top:0px;
  -webkit-animation:walk 3s linear infinite;
  animation:walk 3s linear infinite;
}
.foot-print-2 {
  opacity:0;
  position:absolute;
  left:50px;
  top:0px;
  -webkit-animation:walk 3s linear infinite 0.25s;
  animation:walk 3s linear infinite 0.25s;
}
.foot-print-3 {
  opacity:0;
  position:absolute;
  left:90px;
  top:0px;
  -webkit-animation:walk 3s linear infinite 0.5s;
  animation:walk 3s linear infinite 0.5s;
}
.foot-print-4 {
  opacity:0;
  position:absolute;
  left:130px;
  top:0px;
  -webkit-animation:walk 3s linear infinite 0.75s;
  animation:walk 3s linear infinite 0.75s;
}
.foot-print-5 {
  opacity:0;
  position:absolute;
  left:170px;
  top:0px;
  -webkit-animation:walk 3s linear infinite 1s;
  animation:walk 3s linear infinite 1s;
}       

    
/* walking effect animation keyframes */
    
@-webkit-keyframes walk {
  25%  {opacity: 1;}
  100% {opacity: 0;}
}
    
@keyframes walk {
  /* appear */
  25%  {opacity: 1;}
  /* disappear */
  100% {opacity: 0;}
}