* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
}

body {
  width: 100%;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(45deg, #0a0a0a, #3a4452);
}

.calculator {
  border: 1px solid #717377;
  padding: 20px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.05);
  box-shadow: 0px 3px 15px rgba(113, 115, 119, 0.5);
  backdrop-filter: blur(10px);
}

.display input {
  width: 320px;
  border: none;
  padding: 24px;
  margin: 10px 0 20px 0;
  background: transparent;
  box-shadow: 0px 3px 15px rgba(84, 84, 84, 0.1);
  font-size: 40px;
  text-align: right;
  cursor: pointer;
  color: #ffffff;
  border-radius: 10px;
}

.display input::placeholder {
  color: #ffffff;
}

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

button {
  border: none;
  width: 60px;
  height: 60px;
  margin: 5px;
  border-radius: 50%;
  background: transparent;
  color: #ffffff;
  font-size: 20px;
  box-shadow: -8px -8px 15px rgba(255, 255, 255, 0.1),
               5px 5px 15px rgba(0, 0, 0, 0.2);
  cursor: pointer;
  transition: all 0.2s ease;
}

button:active {
  transform: scale(0.95);
  box-shadow: inset 4px 4px 10px rgba(0, 0, 0, 0.5);
}

.operator {
  color: #fb7c14;
}

.equal {
  background-color: #fb7c14;
  color: #ffffff;
}