body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #f4f4f4;
}

.calculator {
    width: 300px;
    background-color: #333;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.5);
}

.display {
    margin-bottom: 20px;
}

.display input {
    width: 100%;
    height: 60px;
    font-size: 24px;
    text-align: right;
    padding: 0 10px;
    box-sizing: border-box;
    border: none;
    border-radius: 5px;
    background-color: #eee;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 10px;
}

button {
    height: 50px;
    font-size: 18px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    background-color: #4a4a4a;
    color: white;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #5a5a5a;
}

button:active {
    background-color: #3a3a3a;
}

.equals {
    background-color: #f5913e;
    grid-column: span 1;
}

.equals:hover {
    background-color: #ff9f4d;
}

button:nth-child(1),
button:nth-child(2) {
    background-color: #a5a5a5;
    color: black;
}

button:nth-child(1):hover,
button:nth-child(2):hover {
    background-color: #b5b5b5;
}