body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f0f0;
    font-family: Arial, sans-serif;
}

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

.calculator-display {
    width: 100%;
    height: 60px;
    background-color: #444;
    color: #fff;
    font-size: 2.5em;
    text-align: right;
    padding: 10px;
    border: none;
    border-radius: 5px;
    margin-bottom: 15px;
    box-sizing: border-box; /* Include padding in width */
}

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

.calculator-buttons button {
    width: 100%;
    height: 60px;
    font-size: 1.5em;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    background-color: #666;
    color: #fff;
    transition: background-color 0.2s;
}

.calculator-buttons button:hover {
    background-color: #888;
}

.calculator-buttons button.operator {
    background-color: #f79f1b;
}

.calculator-buttons button.operator:hover {
    background-color: #e08e0b;
}

.calculator-buttons button.clear,
.calculator-buttons button.delete {
    background-color: #d9534f;
}

.calculator-buttons button.clear:hover,
.calculator-buttons button.delete:hover {
    background-color: #c9302c;
}

.calculator-buttons button.equals {
    background-color: #5cb85c;
    grid-column: span 2; /* Make equals button span two columns */
}

.calculator-buttons button.equals:hover {
    background-color: #4cae4c;
}

.calculator-buttons button.zero {
    grid-column: span 2; /* Make zero button span two columns */
}