body {
  margin: 0;
  padding: 0;
  height: 100vh;
  background: linear-gradient(135deg, #e8f0f7, #fdfdfd);
  background-attachment: fixed;
  background-size: cover;
  font-family: 'Segoe UI', sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
}


.calculator-container {
  background: #ffffff;
  padding: 30px;
  border-radius: 16px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
  text-align: center;
  width: 320px;
}

.calculator-container h2 {
  margin-bottom: 20px;
  color: #1e1e2f;
  font-size: 1.8rem;
}

#display {
  width: 100%;
  height: 50px;
  font-size: 1.5rem;
  text-align: right;
  padding: 10px;
  border: none;
  border-radius: 8px;
  margin-bottom: 15px;
  background: #ffffff;
  color: #2d3436;
  box-shadow: inset 0 2px 5px rgba(0,0,0,0.05);
}

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

button {
  padding: 14px;
  font-size: 1.1rem;
  border: none;
  border-radius: 8px;
  background-color: #1e1e2f;
  color: white;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s ease;
}

button:hover {
  background-color: #2d2d44;
}

button:active {
  transform: scale(0.97);
}

button:nth-child(2),
button:nth-child(3),
button:nth-child(4),
button:nth-child(8),
button:nth-child(12),
button:nth-child(16) {
  background-color: #00b894;
}

button:nth-child(20) {
  background-color: #0984e3;
}

button:nth-child(20):hover {
  background-color: #0a6fd1;
}

.zero {
  grid-column: span 2;
}
/* Page Load Animation */
.page-animate {
  opacity: 0;
  transform: translateY(40px);
  animation: fadeSlideIn 0.6s ease-out forwards;
}

@keyframes fadeSlideIn {
  0% {
    opacity: 0;
    transform: translateY(40px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}
body {
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', sans-serif;
  background: linear-gradient(180deg, #f0f4f8, #ffffff);
  color: #333;
}

.calculator-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 30px 20px;
}

.calculator-section {
  width: 100%;
  max-width: 400px;
  background: #fff;
  padding: 25px;
  border-radius: 12px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.07);
  text-align: center;
}

#display {
  width: 100%;
  padding: 12px;
  font-size: 1.2rem;
  text-align: right;
  margin-bottom: 20px;
  border: 1px solid #ccc;
  border-radius: 8px;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.buttons button {
  padding: 15px;
  font-size: 1rem;
  border: none;
  border-radius: 8px;
  background-color: #0077b6;
  color: white;
  transition: background 0.3s;
}

.buttons button:hover {
  background-color: #0096c7;
}

.description-section {
  max-width: 600px;
  margin-top: 40px;
  background-color: #f1faff;
  padding: 25px;
  border-radius: 12px;
  text-align: center;
  box-shadow: 0 6px 16px rgba(0,0,0,0.04);
}

.description-section h3 {
  font-size: 1.6rem;
  color: #0077b6;
  margin-bottom: 16px;
}

.description-section ul {
  list-style: none;
  padding-left: 0;
}

.description-section li {
  margin: 10px 0;
}

@media (max-width: 500px) {
  .calculator-section,
  .description-section {
    width: 90%;
    padding: 20px;
  }

  #display {
    font-size: 1rem;
  }

  .buttons button {
    padding: 12px;
    font-size: 0.9rem;
  }

  .description-section h3 {
    font-size: 1.3rem;
  }
}