* {
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
}

body {
  margin: 0;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(135deg, #0f172a, #1e293b);
}

.calculator {
  width: 340px;
  padding: 20px;
  border-radius: 25px;
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(255,255,255,0.1);
  box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}

.display {
  padding: 15px;
  border-radius: 15px;
  margin-bottom: 15px;
  background: rgba(0,0,0,0.3);
  backdrop-filter: blur(10px);
  color: white;
  text-align: right;
}

.history {
  font-size: 14px;
  color: rgba(255,255,255,0.6);
  min-height: 20px;
}

.result {
  font-size: 32px;
  font-weight: 600;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

button {
  border: none;
  padding: 15px;
  border-radius: 15px;
  font-size: 16px;
  cursor: pointer;
  color: white;
  background: rgba(255,255,255,0.05);
  box-shadow:
    5px 5px 10px rgba(0,0,0,0.4),
    -5px -5px 10px rgba(255,255,255,0.05);
  transition: all 0.15s ease;
}

button:active {
  transform: scale(0.92);
  box-shadow: inset 3px 3px 6px rgba(0,0,0,0.5);
}

.number {
  background: rgba(255,255,255,0.07);
}

.operator {
  background: rgba(148,163,184,0.2);
}

.equals {
  background: #22c55e;
  grid-column: span 2;
  box-shadow: 0 5px 20px rgba(34,197,94,0.5);
}

.clear {
  background: #ef4444;
  grid-column: span 2; /* 🔥 sesuai permintaan */
  box-shadow: 0 5px 20px rgba(239,68,68,0.5);
}

.delete {
  background: #3b82f6;
  box-shadow: 0 5px 20px rgba(59,130,246,0.5);
}