@import url('https://fonts.cdnfonts.com/css/digital-numbers');
@import url('https://fonts.googleapis.com/css2?family=Orbitron:wght@700&family=Poppins:wght@500&display=swap');

body {
  margin: 0;
  padding: 0;
  background: #ffffff;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.calculator {
  width: 300px;
  background-color: #000;
  border-radius: 20px;
  padding: 20px;
  box-sizing: border-box;
}

.screen {
  background-color: #222;
  color: #0f0;
  height: 60px;
  font-size: 38px;
  text-align: right;
  padding: 10px 15px;
  border-radius: 10px;
  margin-bottom: 20px;
  font-family: 'Digital Numbers', sans-serif;
  overflow-x: auto;
}

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

button {
  height: 60px;
  font-size: 24px;
  background-color: #333;
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-family: 'Poppins', sans-serif;
}

button.back{
  height: 60px;
  font-size: 30px;
  font-weight: bolder;
  background-color: #333;
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-family: 'Poppins', sans-serif;
}

button:active {
  background-color: #444;
}

.clear {
  background-color: #d32f2f;
  color: white;
}

.equal {
  background-color: #2e7d32;
  color: white;
}