html {
    padding: 0%;
    margin: 0%;
    box-sizing: border-box;
}
body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f4f4f9;
    margin: 0;
}

.calculator {
    background: #ffffff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    text-align: center;
}

.display {
    width: 92.5%;
    padding: 10px;
    font-size: 1.5rem;
    border: 2px solid #ccc;
    border-radius: 5px;
    margin-bottom: 15px;
    text-align: right;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}
button {
    padding: 15px;
    font-size: 1.2rem;
    border: none;
    border-radius: 5px;
    background: #007BFF;
    color: white;
    cursor: pointer;
    transition: background 0.3s;
}
button:hover {
    background: #0056b3;
}
button[data-operation] {
    background: #28a745;
}
button[data-operation]:hover {
    background: #1e7e34;
}
button[data-clear] {
    background: #dc3545;
}
button[data-clear]:hover {
    background: #b21f2d;
}