if (isNaN(gi) || gi < 0 || gi >= groups.length) return;
var allBtns = switchEl.querySelectorAll('button');
for (var i = 0; i < allBtns.length; i++) { allBtns[i].classList.remove('active'); allBtns[i].style.background='#333'; allBtns[i].style.color='#999'; }
btn.classList.add('active'); btn.style.background='var(--primary,#c12c2c)'; btn.style.color='#fff';
var grid = document.getElementById('episodeGrid');
if (!grid || !groups[gi] || !groups[gi].items) return;
var html = '';
for (var j = 0; j < groups[gi].items.length; j++) {
var ep = groups[gi].items[j];
html += '' + ep.name + '';
}
grid.innerHTML = html;
});
})();