/* Blue Header Style */
header {
    text-align: center;
    background-color: #007bff; /* Blue background */
    color: white; /* White text */
    padding: 20px;
    font-size: 1.8rem;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2); /* Subtle shadow for depth */
}

/* Calculator Container */
.calculator {
    max-width: 400px;
    margin: 50px auto;
    padding: 20px;
    background: #ffffff;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

/* Display Section */
.calculator-display {
    margin-bottom: 20px;
}

.calculator-display input {
    width: 100%;
    height: 50px;
    font-size: 1.5rem;
    text-align: right;
    border: 1px solid #ccc;
    border-radius: 5px;
    padding: 5px;
    background-color: #f8f8f8;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* Button Section */
.calculator-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr); /* Four buttons per row */
    gap: 10px; /* Space between buttons */
}

.calculator-buttons button {
    height: 50px;
    font-size: 1.2rem;
    color: #333;
    background-color: #e9ecef;
    border: 1px solid #ddd;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.calculator-buttons button:hover {
    background-color: #d4f3ff;
}

.calculator-buttons button:active {
    background-color: #a8d8f0;
}