setProgressBarValue( progress ) {

		if( this.progressBar ) {

			this.progressBarPlayhead.style.transform = `translateY(${progress * this.progressBarScrollableHeight}px)`;

			this.getAllPages()
				.filter( page => page.progressBarSlide )
				.forEach( ( page ) => {
					page.progressBarSlide.classList.toggle( 'active', page.active === true );

					page.scrollTriggers.forEach( ( trigger, i ) => {
						page.scrollTriggerElements[i].classList.toggle( 'active', page.active === true && trigger.active === true );
					} );
				} );

			this.showProgressBar();

		}

	}
Moves the progress bar playhead to the specified position.

@param {number} progress 0-1