body {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  height: 100vh;
  background: linear-gradient(135deg, #2c2c54, #1e1e2f);
  font-family: 'Segoe UI', sans-serif;
}

.container {
  background-color: #1e1e2f;
  width: 400px;
  border-radius: 20px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.5);
  display: flex;
  flex-direction: column;
  padding: 20px;
}

.display {
  background-color: #2c2c54;
  border-radius: 15px;
  margin-bottom: 15px;
  display: flex;
  justify-content: space-between;
  padding: 10px 15px;
  color: #fff;
  font-size: 1.5rem;
  min-height: 50px;
  box-shadow: inset 0 4px 8px rgba(0,0,0,0.3);
}

.buttonContainer {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.set1, .set2, .set3, .set4 {
  display: flex;
  justify-content: space-between;
}

button {
  flex: 1;
  margin: 5px;
  padding: 15px 0;
  border-radius: 12px;
  border: none;
  background: linear-gradient(145deg, #6a4c93, #9b59b6);
  color: #fff;
  font-size: 1.2rem;
  cursor: pointer;
  box-shadow: 0 4px 8px rgba(0,0,0,0.3);
  transition: all 0.2s ease;
}

button:hover {
  background: linear-gradient(145deg, #9b59b6, #6a4c93);
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0,0,0,0.4);
}

button:active {
  transform: translateY(0);
  box-shadow: 0 3px 6px rgba(0,0,0,0.2);
}

.btnEqual {
  background-color: #e67e22;
}

.btnClr {
  background-color: #c0392b;
}