Act as a senior React developer with 5+ years of experience building complex web applications. Explain how to use React Portals to render children into a DOM node that exists outside the parent component's hierarchy. Cover the following key points: 1) The purpose of [PORTALS] in React and when to use them, 2) How to set up a [TARGET_DOM_NODE] outside the root element, 3) The syntax for creating a portal using [REACT_DOM.createPortal], and 4) Common use cases like modals, tooltips, and global notifications. Provide a complete code example demonstrating portal implementation for a [MODAL_COMPONENT] that renders outside the main app container. Include best practices for accessibility and event bubbling considerations.