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

.new-user-wrapper {
  .user-nav {
    flex-direction: column;

    > li {
      width: 100%;

      .d-icon {
        margin-right: 0.5em;
      }

      &:not(:first-of-type) {
        border-top: 1px solid var(--primary-low);
      }

      > a,
      button {
        padding: 1em 0.75em;
        width: 100%;
      }
    }
  }

  .user-nav-dropdown-list-item {
    flex-direction: column;
  }

  .user-nav-dropdown-chevron {
    margin-left: auto;
  }

  .user-nav-dropdown-button {
    width: 100%;
  }

  .user-nav-dropdown-submenu {
    box-sizing: border-box;
    position: relative;
    top: 0;
    box-shadow: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(50%, 1fr));
    padding: 0.5em 0 1em 1.65em;

    li a {
      box-sizing: border-box;
      padding: 0.75em 1em;
      width: 100%;
      @include ellipsis;
    }
  }
}