To customize FilePond's appearance, you can use built-in themes or write your own CSS to override its styles. FilePond includes a default theme, but you can switch themes by including different CSS files or plugins designed for specific looks. For example, adding a dark theme or image preview plugin will change the widget's appearance. To further match your site's branding, use custom CSS selectors targeting FilePond's class names, such as filepond--root, filepond--panel-root, and filepond--drop-label. By overriding these styles, you can adjust colors, borders, spacing, and more, making the uploader feel like a seamless part of your website.