body {
  background-color: #121212;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  font-family: Arial, sans-serif;
}

#calculator {
  background-color: #1e1e1e;
  border-radius: 10px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
  padding: 20px;
  width: 300px;
}

#display {
  width: 100%;
  height: 50px;
  background-color: #000;
  color: #ff0000;
  border: 2px solid #ff0000;
  border-radius: 5px;
  font-size: 2em;
  text-align: right;
  padding: 5px;
  box-sizing: border-box;
  margin-bottom: 15px;
}

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


button {
  height: 60px;
  font-size: 1.5em;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  color: #fff;
  background-color: #333;
  transition: background-color 0.2s ease;
}

button:hover {
  background-color: #555;
}

.digits, .operators {
  background-color: #333;
}

.operators:hover {
  background-color: #555;
}

#equals {
  grid-column: span 2;
  background-color: #ff0000;
}

#equals:hover {
  background-color: #cc0000;
}

#clear {
  background-color: #ff0000;
}

#clear:hover {
  background-color: #cc0000;
}