.content-section {
  --scroll-length: 1.2;
  height: calc( var(--scroll-length) * 100vh );
  width: 100%;
  font-family: Helvetica Neue, Helvetica, Arial, sans-serif;
}
.content-section .content .subheading,
.content-section .content .paragraph {
  opacity: 1;
  opacity: calc( 1 + var(--viewport-y) );
}

.figure {
  width: 100%;
  height: 100vh;
  margin: 0;
  position: absolute;
  top: 0;
  left: 0;
}
.figure > img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: 100%;
  -o-object-fit: cover;
     object-fit: cover;
  -o-object-position: center center;
     object-position: center center;
}

.content {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  max-width: 35em;
  display: grid;
  grid-template-rows: 1fr 1fr;
  color: white;
  padding: 2em;
  font-size: 2.5vmin;
}
.content * {
  text-shadow: 0 0 4vmin rgba(0, 0, 0, 0.25);
}
.content > .header {
  grid-row: 1 / 2;
  display: -webkit-box;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
          flex-direction: column;
  -webkit-box-pack: end;
          justify-content: flex-end;
}
.content > .paragraph {
  grid-row: 2 / 3;
  line-height: 1.5;
}

.heading {
  font-size: 2.75em;
  margin: 0;
}

.subheading {
  font-size: 1.25em;
  font-weight: 600;
  margin-bottom: .5em;
}

/* ---------------------------------- */
.figure {
  --scale: calc(.8 +
    (.2 * var(--scroll-length) * var(--visible-y))
  );
  position: -webkit-sticky;
  position: sticky;
  top: 0;
  left: 0;
  margin: 0;
  display: block;
  overflow: hidden;
  will-change: transform;
  -webkit-transform: scale(var(--scale));
          transform: scale(var(--scale));
}
.figure:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  background-color: black;
  opacity: calc( var(--visible-y) );
}
.figure > img {
  display: block;
  will-change: transform;
  -webkit-transform: scale(calc(1 / var(--scale)));
          transform: scale(calc(1 / var(--scale)));
}

/* ---------------------------------- */
.char {
  display: inline-block;
  opacity: calc(  1 + (  ( var(--viewport-y) * 1.5 ) - var(--char-percent) ) );
}

*,
*:before,
*:after {
  position: relative;
  box-sizing: border-box;
}

.heading,
.intro-heading {
  font-weight: 700;
}




.th_container {
  display: flex;
  height: 100vh;
}

.th_section {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100%;
  overflow: hidden;
  background-size: cover;
  background-position: center;
  color: #fff;
  transition: flex .4s ease;
  position: relative;
}

.th_section .overlay {
  background-color: rgba(0, 0, 0, 0.4);
  width: 100%;
  height: 100%;
  position: absolute;
  transition: background-color .8s ease;
}

.th_section .th_content {
  z-index: 2;
}

.th_section:hover {
  flex: 2;
}

.th_section:hover .overlay {
  background-color: rgba(0, 0, 0, 0.25);
}