.HeaderMenu {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  padding-right: var(--space-xs);
  padding-left: var(--space-xs);
  border-top: var(--control-border-width) solid var(--color-control-bg-border-default);
  border-left: var(--control-border-width) solid var(--color-control-bg-border-default);
  border-right: var(--control-border-width) solid var(--color-control-bg-border-default);
}

  .HeaderMenu-LeftSide,
  .HeaderMenu-RightSide {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-flex: 1;
        -ms-flex: 1 1 auto;
            flex: 1 1 auto;
    -webkit-box-align: center;
        -ms-flex-align: center;
            align-items: center;
  }

  .HeaderMenu-RightSide {
    -webkit-box-pack: end;
        -ms-flex-pack: end;
            justify-content: flex-end;
  }