body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f4f4f4;
}
.calculator {
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    text-align: center;
}
input {
    width: 100%;
    height: 50px;
    text-align: right;
    font-size: 1.5em;
    margin-bottom: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    padding: 5px;
}
.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}
button {
    padding: 15px;
    font-size: 1.2em;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    background: #007BFF;
    color: white;
}
button:hover {
    background: #0056b3;
}
.equal {
    grid-column: span 2;
    background: #28a745;
}
.equal:hover {
    background: #1e7e34;
}
.clear {
    background: #dc3545;
}
.clear:hover {
    background: #c82333;
}