(() => {
    let theme = 'system';
    let language = navigator.language.startsWith('tr') ? 'tr' : 'en';
    try {
        const storedTheme = localStorage.getItem('ascii-pwa-theme');
        const storedLanguage = localStorage.getItem('ascii-pwa-language');
        if (['system', 'light', 'dark'].includes(storedTheme)) theme = storedTheme;
        if (['en', 'tr'].includes(storedLanguage)) language = storedLanguage;
    } catch { /* Preferences remain available without persistent storage. */ }
    document.documentElement.dataset.theme = theme;
    document.documentElement.lang = language;
})();