style.css

* {
  margin: 0;
  padding: 0;
  font-family: 'Quicksand', sans-serif;
  box-sizing: content-box;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #13161a;
  color: white;
}

.app {
  position: relative;
  width: 650px;
  background: #1b1f24;
  border-radius: 10px;
}

.app .pointer {
  position: absolute;
  z-index: 1;
  left: 50%;
  transform: translate3d(-50%, -25px, 0);
  height: 50px;
  filter: drop-shadow(0 0 20px rgba(230, 174, 174, 0.3));
}

.app .scope {
  overflow: hidden;
}

.app .scope .list {
  position: relative;
  display: inline-flex;
  left: 0;
  transform: translate3d(0, 0, 0);
  list-style: none;
  transition: 5s cubic-bezier(0.21, 0.53, 0.29, 0.99);
}

.app .scope .list__item {
  flex-shrink: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  width: 200px;
  height: 160px;
  opacity: 0.5;
  transition: 0.3s ease;
}

.app .scope .list__item:nth-child(2n) {
  background: rgba(0, 0, 0, 0.1);
}

.app .scope .list__item.active {
  opacity: 1;
}

.app .scope .list__item.active img {
  transform: scale(1.05);
}

.app .scope .list__item img {
  width: 80%;
  height: 80%;
  -o-object-fit: contain;
  object-fit: contain;
  transition: 0.3s ease;
}

.app .start {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translate3d(-50%, 20px, 0);
  padding: 8px 25px;
  border: none;
  border-radius: 5px;
  outline: none;
  background: #eb5146;
  color: inherit;
  font-size: 16px;
  font-weight: 500;
  transition: opacity 0.2s ease;
  box-shadow: 0 0 30px 0 rgba(255, 118, 118, 0.2);
  cursor: pointer;
}

.app .start:hover {
  opacity: 0.8;
}