Below is a single HTML file ready for immediate distribution. It includes a high-end, mobile-optimized design, YouTube videos, a photo slideshow, a registration count (50 people), a timer (as of 2025-11-03 17:00), registration saving via localStorage, duplicate prevention, and registration closing processing. If necessary, you can easily replace it with an actual server-side API by following the comments. Note: - Data Storage: Operates via localStorage by default (safely saved in the browser). When integrating with a server, simply replace the saveRegistration and getRegistrationCount functions. - Timezone: Set to 2025-11-03 17:00 KST (+09:00). - Registration Limit: The button automatically closes once 50 spots are reached. Copy and save as a .html file to check it on a mobile browser. ```html If you wish: - We can also modify it to a version integrated with actual server storage APIs (Firebase/Supabase/Google Apps Script). - Color scheme customization to match the event logo/brand colors, video/image replacement, and the addition of detailed program sections are also possible.