demo.css

*,
*::before,
*::after {
  box-sizing: border-box;
}
html {
  font-family: sans-serif;
  line-height: 1.5;
  margin: 0;
  padding: 0;
}
a {
  text-decoration: none;
  color: inherit;
}
body {
  margin: 0;
}
button {
  font-size: 1rem;
  padding: 0;
  outline: none;
  cursor: pointer;
}
body {
  padding: 0 1em;
}
.scrollable {
  height: 300px;
  overflow: auto;
  background: #DDD;
  -webkit-transition: all .2s ease;
          transition: all .2s ease;
}
.scrollable::after {
  content: "";
  display: block;
  height: 1000px;
}
.child {
  background: #FAFFAC;
}
.child.scrolledge-reached {
  -webkit-animation: bounce .2s ease 1;
          animation: bounce .2s ease 1;
}
@-webkit-keyframes bounce {
  50% {
    -webkit-transform: translateY(20px);
            transform: translateY(20px);
  }
  100% {
    -webkit-transform: translateY(0);
            transform: translateY(0);
  }
}
@keyframes bounce {
  50% {
    -webkit-transform: translateY(20px);
            transform: translateY(20px);
  }
  100% {
    -webkit-transform: translateY(0);
            transform: translateY(0);
  }
}
main {
  position: relative;
}
scrolly-data {
  position: absolute;
  top: 0;
  left: 0;
}
.event-list {
  width: 100%;
}
.event-list__item {
  text-align: left;
}