.page-layout {
  min-height: 100%;
  display: flex;
  flex-direction: column;

  .page-header {
    position: fixed;
    width: 100%;
    z-index: $z-header;

    // Defensive styles in case header height goes over 100px, causing
    // the left gutter menu to be on top of the header.
    height: $header-height;
    overflow: hidden;
  }

  .page-body {
    display: flex;
    flex: 1;
    flex-direction: row;
    justify-content: space-between;
    margin-top: $header-height;

    .page-column {
      flex: 1;

      &.is-left {
        min-width: $gutter-width;
        max-width: $gutter-width;
        position: fixed;
        bottom: 0;
        top: $header-height;
        z-index: $z-gutter;
        background: $white;
      }

      &.is-right {
        margin-left: $gutter-width;
        overflow-x: auto;
      }

      @media #{$mq-hidden-gutter} {
        &.is-left {
          top: 0;
          transform: translateX(-$gutter-width);
          transition: transform ease-in-out 0.2s;

          &.is-open {
            transform: translateX(0);
          }
        }

        &.is-right {
          margin-left: 0;
        }
      }
    }
  }
}

.page-layout {
  min-height: 100%;
  display: flex;
  flex-direction: column;

  .page-header {
    position: fixed;
    width: 100%;
    z-index: $z-header;

    // Defensive styles in case header height goes over 100px, causing
    // the left gutter menu to be on top of the header.
    height: $header-height;
    overflow: hidden;
  }

  .page-body {
    display: flex;
    flex: 1;
    flex-direction: row;
    justify-content: space-between;
    margin-top: $header-height;

    .page-column {
      flex: 1;

      &.is-left {
        min-width: $gutter-width;
        max-width: $gutter-width;
        position: fixed;
        bottom: 0;
        top: $header-height;
        z-index: $z-gutter;
        background: $white;
      }

      &.is-right {
        margin-left: $gutter-width;
      }

      @media #{$mq-hidden-gutter} {
        &.is-left {
          top: 0;
          transform: translateX(-$gutter-width);
          transition: transform ease-in-out 0.2s;

          &.is-open {
            transform: translateX(0);
          }
        }

        &.is-right {
          margin-left: 0;
        }
      }
    }
  }
}

Make sure tooltips show up over the top of the side bar
Make sure tooltips show up over the top of the side bar
