<style>
    .invisalign-calculator-container {
        font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        background: linear-gradient(135deg, #f5f7fa, #c3cfe2);
        padding: 2em;
        border-radius: 15px;
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        max-width: 500px;
        margin: 2em auto;
        color: #333;
    }

    .calculator-header {
        text-align: center;
        margin-bottom: 2em;
    }

    .calculator-header h2 {
        font-size: 2em;
        color: #1a73e8;
        margin-bottom: 0.2em;
    }

    .calculator-header p {
        color: #5f6368;
    }

    .form-group {
        margin-bottom: 1.5em;
    }

    .form-group label {
        display: block;
        margin-bottom: 0.5em;
        font-weight: 600;
        color: #3c4043;
    }

    .form-control {
        width: 100%;
        padding: 0.8em;
        border: 1px solid #ddd;
        border-radius: 8px;
        background-color: #fff;
        font-size: 1em;
        transition: border-color 0.3s;
    }

    .form-control:focus {
        border-color: #1a73e8;
        outline: none;
    }

    input[type="range"] {
        -webkit-appearance: none;
        appearance: none;
        width: 100%;
        height: 8px;
        background: #ddd;
        border-radius: 5px;
        outline: none;
        opacity: 0.7;
        transition: opacity .2s;
    }

    input[type="range"]::-webkit-slider-thumb {
        -webkit-appearance: none;
        appearance: none;
        width: 20px;
        height: 20px;
        background: #1a73e8;
        cursor: pointer;
        border-radius: 50%;
        transition: background .3s;
    }

    input[type="range"]::-moz-range-thumb {
        width: 20px;
        height: 20px;
        background: #1a73e8;
        cursor: pointer;
        border-radius: 50%;
    }

    input[type="range"]:hover {
        opacity: 1;
    }

    .range-value {
        display: block;
        text-align: right;
        font-size: 0.9em;
        color: #5f6368;
    }

    .calculator-footer {
        text-align: center;
        margin-top: 2em;
        padding-top: 1.5em;
        border-top: 1px solid #ddd;
    }

    .calculator-footer h3 {
        font-size: 1.8em;
        color: #1e8e3e;
        margin-bottom: 0.5em;
    }

    .calculator-footer p {
        color: #5f6368;
    }

    @media (max-width: 600px) {
        .invisalign-calculator-container {
            padding: 1.5em;
        }

        .calculator-header h2 {
            font-size: 1.8em;
        }
    }
</style>