/**
 * Everything that keeps arbitrary consumer HTML inside its bubble.
 *
 * The widget has no say over what goes in a message, so the containment is
 * structural rather than a list of rules per element: the content box declares
 * its own size, refuses to grow past the bubble, and contains its layout and
 * paint so a stray position or margin cannot escape.
 */
export const contentStyles: import("lit").CSSResult;