How to Create a Full-Screen Video Background with CSS

Full-screen video backgrounds create cinematic hero sections that immediately capture visitor attention. The video fills the entire viewport while text and UI elements overlay the video content.

The technique: use an HTML5 video element with object-fit: cover to fill the viewport, position it fixed or absolute, and layer content on top with z-index. Add a semi-transparent overlay between the video and text for readability.

Best practices: Always include a fallback background image and muted autoplay for mobile compatibility. Keep video files under 5MB and use modern formats (WebM + MP4) for cross-browser support.