(function () {
    var KEY = 'qihuo-theme';

    function apply(theme) {
        document.documentElement.setAttribute('data-theme', theme);
        try {
            localStorage.setItem(KEY, theme);
        } catch (e) { /* ignore */ }
        var btn = document.getElementById('theme-toggle');
        if (btn) {
            btn.setAttribute('data-active', theme);
            btn.setAttribute('aria-label', theme === 'light' ? '切换到深色' : '切换到浅色');
        }
    }

    var saved = null;
    try {
        saved = localStorage.getItem(KEY);
    } catch (e) { /* ignore */ }

    if (saved === 'light' || saved === 'dark') {
        apply(saved);
    } else {
        var prefersLight = window.matchMedia && window.matchMedia('(prefers-color-scheme: light)').matches;
        apply(prefersLight ? 'light' : 'dark');
    }

    document.addEventListener('DOMContentLoaded', function () {
        var btn = document.getElementById('theme-toggle');
        if (!btn) return;
        btn.addEventListener('click', function () {
            var cur = document.documentElement.getAttribute('data-theme') || 'dark';
            apply(cur === 'dark' ? 'light' : 'dark');
        });
    });
})();