ul {
  width: 40%;

  margin-top: 10px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

ul li {
  height: 25px;
  padding: 10px;
  flex-grow: 1;

  box-shadow: 0px 1px 4px rgba(0, 0, 0, 0.4);
  border: 2px solid white;

  text-align: center;
}

ul li:hover {
  border-color: pink;
  cursor: pointer;
}