We’ve looked into this thoroughly. Because the Aethos app uses Sendbird’s out-of-the-box chat screens, the appearance of link messages is controlled entirely by Sendbird’s internal theming system. Sendbird automatically assigns background colors for certain message types (including link previews) based on the app’s primary background and text colors.

Since Aethos is set to a dark theme, Sendbird forces those link messages onto a contrasting light background for readability. This isn’t something we can override without fully replacing Sendbird’s UI components, which would require a custom chat build rather than the standard package.

For now, this behavior can’t be changed, and formatting options like bold/italics aren’t supported in the default Sendbird UI. If Sendbird exposes more customization options in a future release, we can revisit it.