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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

HTML

            
              <div class="guide-content">
  <section style="height: 110vh;">
    <header>
      <h2>Scroll Down &#8597;</h2>
    </header>
  </section>
  <section>
    <header>
      <h2>Animating Variable Font Headlines</h2>
    </header>
  </section>
</div>
            
          
!

CSS

            
              h2 {
	font-family: "Variable Bahnschrift", "FF DIN", "Franklin Gothic", "Helvetica Neue", sans-serif;
	font-feature-settings: "kern" 1;
	line-height: 1.2;
	text-transform: uppercase;
	letter-spacing: .05em;
	color: #424f5e;
  font-size: 2.25em;
  opacity: .8;
	font-weight: 100;

	/* TranslateZ sends el to its own rendering layer */
	transform: scale(.8) translateZ(1px);
	transition: font-weight 1s, opacity 1s, transform 1s;
  text-align: center;
  margin-bottom: 500px;
}

h2.in-view {
	opacity: .99;
	font-weight: 900;
	transform: scale(1) translateZ(1px);
}
            
          
!

JS

            
              	// ANIMATE FONT-WEIGHT ON HEADINGS WHEN THEY ARE IN VIEW
	const animateHeader = function(guideHeader, ratio) {
		if (ratio > 0) {
			if (false && guideHeader.tagName === 'H2') {
					guideHeader.classList.add('in-view');
			} else {
				guideHeader.classList.add('in-view');
			}
		} else {
			guideHeader.classList.remove('in-view');
		}
	};

  // Setup the Intersection observer to watch the boxes we care about
  // and when they're in view fire the animation function to add our
  // CSS classes
	const guideHeaders = document.querySelectorAll('.guide-content h2');
	const guideHeadersObserver = new IntersectionObserver((entries) => {
		return entries.forEach((e) => {
			animateHeader(e.target, e.intersectionRatio);
		});
	}, { threshold: 0.1 });
	for (const guideHeader of guideHeaders) {
		guideHeadersObserver.observe(guideHeader);
		guideHeadersObserver.observe(guideHeader.closest('section'));
	}
            
          
!
999px

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