* {
  box-sizing: border-box;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background: linear-gradient(to right, #0f2027, #203a43, #2c5364);
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.calculator {
  background-color: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 20px;
  padding: 20px;
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.3);
  width: 320px;
}

.display {
  background-color: #222;
  color: white;
  padding: 20px;
  text-align: right;
  border-radius: 10px;
  margin-bottom: 20px;
  min-height: 80px;
  word-wrap: break-word;
  word-break: break-all;
}

#current-operand {
  font-size: 2rem;
  font-weight: bold;
}

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

button {
  padding: 15px;
  font-size: 1.2rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  background-color: #eee;
  transition: 0.2s;
}

button:hover {
  background-color: #ddd;
}

.operator {
  background-color: #ff9500;
  color: white;
}
.operator:hover {
  background-color: #e68600;
}

.span-two {
  grid-column: span 2;
}

.btn-clear {
  background-color: #ff3b30;
  color: white;
}