discourse/plugins/chat/assets/stylesheets/mobile/chat-navbar.scss

.c-navbar {
  gap: 0.75rem;
  &-container {
    max-width: 100vw;
    padding-inline: 0.25rem;
  }
  &__actions {
    margin-right: 0.5rem;
  }
  &__back-button {
    align-self: stretch;
  }
  &.-full-title {
    .c-navbar {
      &__actions,
      &__back-button {
        height: calc(var(--chat-header-offset) - 2px) !important;
      }
      &__title {
        padding-block: calc(1rem + 2px);
      }
    }
    left: 0.25rem;
    width: calc(100% - 0.5rem);
  }
}