@import url('https://fonts.googleapis.com/css2?family=Rubik&display=swap');

body {
  margin: 0;
  padding: 0;
  font-family: 'Rubik', sans-serif;
  background: linear-gradient(135deg, #b8c6db, #f5f7fa);
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.main {
  display: flex;
  flex-direction: column;
  align-items: center;
}


.title {
  font-size: 32px;
  margin-bottom: 20px;
  font-weight: bold;
  color: skyblue;
}

.calculator {
  background-color: #ffffff;
  padding: 25px;
  border-radius: 20px;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.1);
  width: 320px;
  text-align: center;
}

#display {
  width: 90%;
  height: 60px;
  font-size: 28px;
  border-radius: 20px;
  outline: none;
  padding: 10px 20px;
  margin-bottom: 20px;
  border-radius: 12px;
  background-color: #f2f2f2;
  text-align: right;
  box-shadow: inset 0 2px 5px rgba(0,0,0,0.05);
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 70px);
  gap: 15px;
  justify-content: center;
}

button {
  height: 60px;
  font-size: 20px;
  border: none;
  border-radius: 14px;
  background-color: #e0e0e0;
  cursor: pointer;
  transition: 0.2s ease;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.08);
}

button:hover {
  background-color: #d1d1d1;
}

button:active {
  transform: scale(0.97);
}

button:nth-child(4n) {
  background-color: #f7a440;
  color: white;
}

button:nth-child(4n):hover {
  background-color: #e2952f;
}

button:nth-child(17) {
  grid-column: span 2;
  background-color: #4caf50;
  color: white;
}

button:nth-child(17):hover {
  background-color: #449d48;
}

button:nth-child(1) {
  background-color: #ff5c5c;
  color: white;
}

button:nth-child(1):hover {
  background-color: #e64545;
}