discourse/app/assets/stylesheets/desktop/group.scss

.group-nav {
  .group-dropdown {
    margin-right: 10px;
  }
}

.group-navigation {
  width: 15%;
  background-color: transparent;

  li {
    border: none;

    a {
      color: var(--primary-med-or-secondary-high);
      padding: 8px 0;

      &.active {
        background-color: transparent;
        font-weight: bold;
        color: var(--primary);

        &:after {
          display: none;
        }
      }
    }
  }
}

.group-activity-outlet,
.group-messages-outlet,
.group-manage-outlet {
  width: 85%;
}

.group-manage {
  .form-horizontal {
    button {
      float: none;
    }
  }
}

.groups-form.groups-notifications-form {
  width: 500px;
  max-width: 100%;
}