cosmic drift（f94b6dbd）

Use this MotionSites background video as a looping website background asset.
Title: Cosmic Drift
Category: background
License: 免费
Video URL: https://d8j0ntlcm91z4.cloudfront.net/user_38xzZboKViGWJOttwIXH07lWA1P/hf_20260314_131748_f2ca2a28-fed7-44c8-b9a9-bd9acdd5ec31.mp4
Local thumbnail: thumbnails/f94b6dbd-dc43-4fb6-ad25-19550acfa3bc.jpg
Implementation requirements:
- Render the video as a muted, autoplay, looped, playsInline background layer.
- Use object-fit: cover and keep the focal motion visible on desktop and mobile.
- Add a readable overlay only when foreground text needs contrast.
- Keep controls hidden for decorative background use, and provide a poster/thumbnail fallback.
- Respect the MotionSites authorization state before using this asset in a commercial project.