body .calculator-container {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #ffffff;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 650px;
    margin: 2rem auto;
}

.calculator-container h1,
.calculator-container h2 {
    text-align: center;
    color: #2c3e50;
}

.calculator-container h1 {
    margin-top: 0;
    margin-bottom: 1.5rem;
}

.calculator-container h2 {
    margin-top: 1.5rem;
    margin-bottom: 1rem;
    font-size: 1.2rem;
    border-top: 1px solid #e0e0e0;
    padding-top: 1.5rem;
}

.calculator-container .form-group {
    margin-bottom: 1rem;
    display: flex;
    flex-direction: column;
}

.calculator-container .form-group label {
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #555;
}

.calculator-container .form-group input {
    padding: 0.75rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 1rem;
    transition: border-color 0.2s;
    background-color: #fff;
    color: #333;
}

.calculator-container .form-group input:focus {
    outline: none;
    border-color: #007bff;
    box-shadow: 0 0 0 2px rgba(0, 123, 255, 0.25);
}

.calculator-container .form-group.result input {
    background-color: #e9ecef;
    font-weight: bold;
    color: #495057;
    cursor: not-allowed;
}

.calculator-container .form-actions {
    margin-top: 1.5rem;
    text-align: center;
}

.calculator-container .form-actions button {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    color: #fff;
    background-color: #15416e;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.calculator-container .form-actions button:hover {
    background-color: #18BA60;
}

/* --- Responsive Styles for Mobile --- */
@media (max-width: 600px) {
    body .calculator-container {
        padding: 1rem;
        margin: 1rem;
    }

    .calculator-container h1 {
        font-size: 1.5rem;
    }

    .calculator-container h2 {
        font-size: 1rem;
    }

    .calculator-container .form-group input {
        font-size: 0.95rem;
        padding: 0.6rem;
    }

    .calculator-container .form-actions button {
        width: 100%;
        padding: 0.75rem;
        font-size: 1rem;
    }
}