  existingMarker.remove();
            }
            
            const minutesFromStart = (currentTime - guideStartTime) / (1000 * 60);
            const totalMinutes = (guideEndTime - guideStartTime) / (1000 * 60);
            const timePercent = (minutesFromStart / totalMinutes) * 100;
            
            // Only show marker if current time is within the guide window
            if (minutesFromStart >= 0 && minutesFromStart <= totalMinutes) {
                const timeline = document.getElementById(