body {
  transition: all 0.2s cubic-bezier(0.39, 0.575, 0.565, 1);
}

body.has-sticky {
  background-color: darkcyan;
}

.box {
  width: 80vw;
  background-color: cadetblue;
  height: 300px;
  margin: 1rem;
}

.sticky-top {
  background-color: lightslategrey;
  height: 100px;
  position: sticky;
  top: 0;
}

.flexgrid {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.flexgrid .item {
  background-color: bisque;
  flex: 1 0 30%;
}