Method _addStickyStyle

src/cdk/table/sticky-styler.ts:385–400

* Adds the sticky styling to the element by adding the sticky style class, changing position * to be sticky (and -webkit-sticky), setting the appropriate zIndex, and adding a sticky * direction and value.

(
    element: HTMLElement,
    dir: StickyDirection,
    dirValue: number,
    isBorderElement: boolean,
  )

   * direction and value.
   */
  _addStickyStyle(
    element: HTMLElement,
    dir: StickyDirection,
    dirValue: number,
    isBorderElement: boolean,
  ) {
    element.classList.add(this._stickCellCss);
    if (isBorderElement) {
      element.classList.add(this._borderCellCss[dir]);
    }
    element.style[dir] = `${dirValue}px`;
    element.style.zIndex = this._getCalculatedZIndex(element);
    if (this._needsPositionStickyOnElement) {
      element.style.cssText += 'position: -webkit-sticky; position: sticky; ';
    }
  }

  /**
   * Calculate what the z-index should be for the element, depending on what directions (top,