Help for web.nav.style_selector_form

def style_selector_form(all_styles, selected_style, cookies_enabled, cookies_accepted, project):
    options = []
    for src, fname in all_styles:
        label = fname[:-4].upper()
        label = f"GLOBAL: {label}" if src == "global" else f"{src.upper()}: {label}"
        selected = " selected" if fname == selected_style else ""
        options.append(f'<option value="{fname}"{selected}>{label}</option>')

    info = ""
    if cookies_enabled and not cookies_accepted:
        info = "<p><b><a href='/cookies/cookie-jar'>Accept cookies to save your style preference.</a></b></p>"

    # No JS redirect actually needed.
    if cookies_enabled and cookies_accepted:
        return f"""
            {info}
            <form method="post" action="/nav/style-switcher" class="style-form" style="margin-bottom: 0.5em">
                <select id="css-style" name="css" class="style-selector" style="width:100%" onchange="this.form.submit()">
                    {''.join(options)}
                </select>
                <noscript><button type="submit">Set</button></noscript>
            </form>
        """
    else:
        # Preview-only (no saving)
        return f"""
            {info}
            <select id="css-style" name="css" class="style-selector" style="width:100%" onchange="styleSelectChanged(this)">
                {''.join(options)}
            </select>
            <script>
                function styleSelectChanged(sel) {{
                    var val = sel.value;
                    var url = new URL(window.location.href);
                    url.searchParams.set('css', val);
                    window.location.href = url.toString();
                }}
            </script>
        """