ntListener('DOMContentLoaded', function() {
    // Initialize features
    updateLastRefresh();
    
    // Wait for charts to be initialized before making them responsive
    setTimeout(makeChartsResponsive, 1000);
    
    // Add keyboard shortcuts
    document.addEventListener('keydown', function(e) {
        if (e.ctrlKey || e.metaKey) {
            switch(e.key) {
                case 'r':
                    e.preventDefault();
                    refreshDashboard();
                    break;
       