async function createZNode(zIndexVal, { mode } = {}) {
        if (mode === 'global') {
          contentNode = /** @type {HTMLElement} */ (
            await fixture(html`
              <div class="z-index--${zIndexVal}">
                <style>
                  .z-index--${zIndexVal} {
                    z-index: ${zIndexVal};
                  }
                </style>
                I should be on top
              </div>
            `)
          );
        }
        if (mode === 'inline') {
          contentNode = /** @type {HTMLElement} */ (
            await fixture(html` <div>I should be on top</div> `)
          );
          contentNode.style.zIndex = zIndexVal;
        }
        return contentNode;
      }
@param {string} zIndexVal
@param {{ mode?: string }} options