body{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f0f2f5;
    font-family: Arial, sans-serif;
    margin: 0;
}
.calculator{
    background-color: #22252d;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
    width: 300px;
}
#display{
    width: 100%;
    height: 60px;
    border: none;
    border-radius: 10px;
    margin-bottom: 15px;
    text-align: right;
    font-size: 28px;
    box-sizing: border-box;
    background-color: #292d36;
    color: #ffffff;
}
.buttons{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}
button{
    min-height: 55px;
    font-size: 20px;
    font-weight: bold;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    background-color: #292d36;
    color: #ffffff;
    transition: background-color 0.3s transform 0.1s;
}
button:hover{
    background-color: #3f4553;
}
button:active{
    transform: scale(0.90);
}
.btn-op{
    background-color: #ff9500;
    color: white;
}
.btn-clear {
  grid-column: span 2;
  background-color: #ff3b30;
  color: white;
}

.btn-clear:hover {
  background-color: #d63028;
}

.btn-zero {
  grid-column: span 2;
}

.btn-equal {
  grid-row: span 2;
  background-color: #34c759;
  color: white;

}

.btn-equal:hover {
  background-color: #2da84e;
}