* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Arial', sans-serif;
  background: url('photo01.jpg') no-repeat center center fixed;
  background-size: cover;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  color: #ffffff;
  animation: fadeIn 1s ease-in-out;
}

.calculator-container {
  text-align: center;
  background-color: rgba(0, 251, 255, 0.7); 
  border-radius: 20px;
  padding: 30px;
  width: 400px;
  max-width: 90vw;
  box-shadow: 0 8px 15px rgb(21, 0, 255);
  border: 2px solid #000000;
  transform-style: preserve-3d;
  animation: calculatorAnimate 2s ease-in-out infinite alternate;
  transition: transform 0.3s ease;
}

@keyframes calculatorAnimate {
  0% {
      transform: rotateY(0deg);
  }
  100% {
      transform: rotateY(10deg);
  }
}

.logo-img {
  width: 100px;
  height: 100px;
  animation: logoAnimation 3s ease-in-out infinite alternate;
}

@keyframes logoAnimation {
  0% {
      transform: rotate(0deg);
  }
  100% {
      transform: rotate(360deg);
  }
}

.calculator {
  margin-top: 25px;
}

.display {
  width: 100%;
  padding: 20px;
  font-size: 3rem;
  margin-bottom: 30px;
  text-align: right;
  border: 2px solid #000000; 
  border-radius: 10px;
  background: linear-gradient(135deg, #0066cc, #0051ff);
  color: #ffffff;
  box-shadow: 0 0 15px rgb(0, 157, 255);
  animation: glowEffect 1.5s infinite alternate;
}

@keyframes glowEffect {
  0% {
      box-shadow: 0 0 15px rgb(0, 0, 255);
  }
  100% {
      box-shadow: 0 0 30px rgba(0, 0, 255, 0.8);
  }
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 15px;
}

.btn {
  padding: 20px;
  font-size: 2rem;
  border-radius: 12px;
  cursor: pointer;
  background: linear-gradient(135deg, #0066cc, #0080ff);
  border: 2px solid #1f5992;
  transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.4);
  transform-style: preserve-3d;
  outline-offset: 3px;
}

.btn:hover, .btn:focus {
  background: linear-gradient(135deg, #0051ff, #22fff4);
  transform: translateY(-8px) rotateX(10deg);
  box-shadow: 0 6px 12px rgba(0, 255, 255, 0.8);
  outline: none;
}

.btn:active {
  transform: translateY(0) rotateX(0);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.6);
}

.operator {
  background: linear-gradient(135deg, #22fff4, #0051ff);
  color: #000000;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.6);
}

.operator:hover, .operator:focus {
  background: linear-gradient(135deg, #00f0ff, #0077ff);
  outline: none;
  box-shadow: 0 6px 12px rgba(0, 255, 255, 0.8);
}

/* Focus style for accessibility */
.btn:focus-visible {
  outline: 3px solid #00ffff;
  outline-offset: 3px;
}

@keyframes fadeIn {
  0% {
      opacity: 0;
      transform: translateY(-50px);
  }
  100% {
      opacity: 1;
      transform: translateY(0);
  }
}

@media (max-width: 600px) {
  /* Adjust styles for smaller screens */
  .calculator-container {
    width: 100%;
    padding: 20px;
  }

  .display {
    font-size: 2.5rem;
    padding: 15px;
  }

  .btn {
    padding: 15px;
    font-size: 1.6rem;
  }
}

