style.css

body,
html {
  background-color: #111155;
}
#holder {
  display: flex;
  margin: 250px auto;
  max-width: 800px;
  min-width: 400px;
  justify-content: center;
  flex-wrap: wrap;
  border-radius: 15px;
}
.circle {
  width: 100px;
  height: 100px;
  padding: 10px;
  margin: 10px;
  border-radius: 50%;
  background-color: #44a1f2;
  font-family: helvetica;
  color: white;
  display: flex;
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.3);
  align-items: center;
  justify-content: center;
  font-size: 50px;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  -o-user-select: none;
  user-select: none;
  cursor: grab;
}
.circle:active {
  color: purple;
  position: relative;
  top: 1px;
  left: 1px;
  cursor: grabbing;
}
.circle:hover {
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.4);
}