body {
  font-family: 'Arial', sans-serif;
  background: #e0f7fa;
  text-align: center;
  padding: 40px;
}

.container {
  background: white;
  padding: 30px;
  border-radius: 15px;
  display: inline-block;
  box-shadow: 0 0 15px rgba(0, 0, 0, 0.2);
}

select, button {
  padding: 10px;
  font-size: 16px;
  margin: 10px;
}

button {
  background-color: #009688;
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s;
}

button:hover {
  background-color: #00796b;
}

.coin-box {
  margin-top: 30px;
  height: 120px;
  position: relative;
}

.coin {
  width: 100px;
  height: 100px;
  margin: auto;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 1s;
}

.coin img {
  width: 100px;
  height: 100px;
  position: absolute;
  backface-visibility: hidden;
}

#heads {
  transform: rotateY(0deg);
}

#tails {
  transform: rotateY(180deg);
}