CSS Overlay Property Preview
Preview overlay and transition-behavior CSS for top-layer UI elements.
What the CSS Overlay Property does
Preview overlay and transition-behavior CSS for top-layer UI elements. A dialog can keep its overlay transition smooth while it closes Adjust the controls and the preview updates immediately, so you can dial in exactly what you want and copy the result straight into your project — no build step and no account.
One thing to keep in mind: Top-layer behavior differs from ordinary positioned elements.
Private and in your browser
Everything runs locally in your browser. Your input is never uploaded, so the tool stays fast and works offline, and the copy and download buttons always use the current result shown in the output panel.
Frequently Asked Questions
What does the CSS Overlay Property do?
Preview overlay and transition-behavior CSS for top-layer UI elements. A dialog can keep its overlay transition smooth while it closes.
What should I keep in mind?
Top-layer behavior differs from ordinary positioned elements
Does it upload my input?
No. The CSS Overlay Property runs entirely in your browser — your input is never uploaded, and it keeps working offline once the page has loaded.
Practical utilities for front-end design and implementation work.