`).join(''); scheduleSubtitle.textContent = `Based on a ${formatTime(wakeUpTime)} wake-up time. Sunrise is at ${formatTime(sunrise)}.`; resultsSection.classList.remove('hidden'); }; // --- 5. PDF GENERATION --- const handlePdfDownload = () => { const { jsPDF } = window.jspdf; const contentToPrint = document.getElementById('printable-content'); const buttonContainer = document.getElementById('pdf-button-container'); if (!contentToPrint) return; buttonContainer.classList.add('hide-for-pdf'); html2canvas(contentToPrint, { scale: 2, useCORS: true }).then(canvas => { buttonContainer.classList.remove('hide-for-pdf'); const imgData = canvas.toDataURL('image/png'); const pdf = new jsPDF({ orientation: 'portrait', unit: 'pt', format: 'a4' }); const pdfWidth = pdf.internal.pageSize.getWidth(); const canvasWidth = canvas.width; const canvasHeight = canvas.height; const ratio = canvasWidth / pdfWidth; const calculatedHeight = canvasHeight / ratio; pdf.addImage(imgData, 'PNG', 0, 0, pdfWidth, calculatedHeight); pdf.save('Circadian_Rhythm_Schedule.pdf'); }).catch(err => { buttonContainer.classList.remove('hide-for-pdf'); showError('An error occurred while generating the PDF.'); }); }; // --- 6. EVENT LISTENERS --- calculateBtn.addEventListener('click', generateSchedule); downloadPdfBtn.addEventListener('click', handlePdfDownload); });