discourse/app/assets/stylesheets/mobile/personal-message.scss

.archetype-private_message {
  .topic-body .cooked {
    margin-top: 0.5em;
    margin-left: 0;
    padding: 1.5em 1em;
    border-radius: 0.75em var(--border-radius) var(--border-radius)
      var(--border-radius);
  }
  .topic-avatar {
    margin-bottom: -1em; // creates bubble overlap
  }
  .boxed .contents {
    padding: 0;
  }

  .topic-post {
    margin: 0 0 1em;
    article {
      border-top: none;
    }
  }

  .topic-body {
    flex: 1 1 auto;
  }

  .topic-map {
    padding: 1em 0.5em;
    margin-left: 0;
  }

  .post-notice {
    padding: 1em;
    margin: 0 0 1em;
    width: 100%;
  }

  .small-action {
    margin-left: 0;
  }

  .small-action-desc.timegap {
    margin-left: 0;
    padding: 1em 1em 1em 0;
  }

  .small-action:not(.time-gap) {
    padding: 1em;
  }

  .topic-meta-data .names .first.staff {
    flex-basis: 100%;
    & + .second,
    & + .second + .user-title {
      flex-basis: unset;
    }
  }
}