discourse/plugins/chat/assets/stylesheets/common/chat-onebox.scss

.chat-onebox {
  .chat-onebox-body {
    .chat-onebox-title {
      margin-bottom: 3px;
    }

    .chat-onebox-description {
      color: var(--primary-medium);
    }

    .chat-onebox-members-count {
      color: var(--primary-medium);
      margin-top: 1em;
      margin-bottom: 3px;
    }

    .chat-onebox-members {
      align-items: center;
      color: var(--primary-medium);
      display: flex;
      flex-wrap: wrap;

      .avatar {
        aspect-ratio: 30 / 30;
        margin-right: 0.25rem;
      }
    }
  }
}

.chat-drawer-container .chat-message .onebox {
  width: 85%;
  border: 2px solid var(--primary-low);

  header {
    margin-bottom: 0.5em;
  }

  .onebox-body {
    grid-template-rows: auto auto auto;
    overflow: auto;
  }

  h3 {
    @include line-clamp(2);
    font-weight: 500;
    font-size: var(--font-down-1);
  }

  p {
    display: none;
  }
}

.has-full-page-chat .chat-message .onebox:not(img),
.chat-drawer-container .chat-message .onebox {
  margin: 0.5em 0;
  border-width: 2px;

  header {
    margin-bottom: 0.5em;
  }

  h3 a,
  h4 a {
    font-size: 14px;
  }

  pre {
    display: flex;
    max-height: 150px;
  }

  p {
    overflow: hidden;
  }
}