#end-round-button {
  display: block;
  margin: 2em auto;
  background-color: #2d7d4f;
  color: #e0e0e0;
  border: none;
  padding: 15px 30px;
  font-size: 1.2em;
  font-weight: bold;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: center;
}

#end-round-button:hover {
  background-color: #3a9e6a;
  box-shadow: 0 0 10px rgba(45, 125, 79, 0.5);
}

#end-round-button:active {
  transform: scale(0.95);
  background-color: #2c7d4f;
}

#active-display {
  font-size: 1.2em;
  margin: 20px 0;
  text-align: center;
}

/* Add styles for #riffs-container and #piano-keyboard if needed */