discourse/app/assets/stylesheets/mobile/new-user.scss

.new-user-wrapper {
  .user-messages-page & {
    .user-navigation-secondary {
      display: grid;
      grid-template-areas:
        "dropdown controls"
        "nav-pills nav-pills";
      grid-template-columns: 1fr auto;
      font-size: var(--font-up-1);
      gap: 0.5em;

      .category-breadcrumb {
        grid-area: dropdown;
      }

      .horizontal-overflow-nav {
        grid-area: nav-pills;
      }

      .navigation-controls {
        grid-area: controls;
        font-size: var(--font-down-2);

        .btn {
          padding: 0.5em 1em;
        }

        .d-button-label,
        .select-kit-header-wrapper .name {
          display: none;
        }
        .d-icon {
          margin: 0;
        }
      }

      .user-nav-messages-dropdown {
        max-width: unset;
      }

      .combo-box-header {
        font-size: var(--font-0);
      }
    }

    tbody {
      border-top-width: 1px;
    }

    .user-content {
      margin: 0;
      table {
        margin-top: -1px; // align under nav border
      }
    }
  }
}

.new-user-content-wrapper {
  .user-content {
    margin-top: 1em;
  }
}