Prompt pattern
Keep pop-ups focused and easy to dismiss
An overlay handles one short task without trapping or surprising the visitor.
Fills the component part of a prompt.
Open the overlay only after a visitor chooses an action, and give it one heading, one task, and a visible close button. Let Escape and a click outside close it, then return keyboard focus to the control that opened it. Do not show it automatically on page load or place a second overlay on top.
Use this component pattern when it changes the result the agent should produce. It provides one concrete direction without deciding unrelated parts of the website.