Daily Prebuilt offers a straightforward solution for integrating video chat into applications with minimal coding, but customization is often necessary to align with specific app layouts and user experiences. Adjusting the Daily Prebuilt's iframe to fit varying screen sizes and maintain a consistent aspect ratio can be achieved through different methods, such as using CSS or JavaScript. The CSS aspect-ratio property allows for responsive design by setting the width to fill the parent container while automatically adjusting the height, but JavaScript provides an alternative with an event listener that recalculates dimensions on window resize. For React users, a useEffect hook can manage the resizing process, ensuring the iframe maintains the desired aspect ratio. Each method has its considerations, such as browser support and personal coding preferences, and may require performance optimizations like throttling resize events to prevent excessive re-rendering. The choice between CSS and JavaScript solutions depends on the specific project requirements and developer comfort with each approach.