.threshold {
  position: sticky;
  width: 100%;
  height: 1px;
  background-color: red;
  z-index: 9999999999;
}
.threshold--top {
  top: 50%;
}

p, h1, h3 {
  font-family: sans-serif;
  line-height: 1.8;
  color: #666;
  font-size: 0.9rem;
  font-weight: 300;
}

h1 {
  font-size: 3rem;
  font-weight: 200;
  margin-bottom: 0;
}

h3 {
  font-size: 2.4rem;
  font-weight: 200;
  margin-bottom: 0;
}

.text {
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  margin: 0 auto;
}
.text p {
  width: 40%;
}

.image {
  opacity: 0;
  transition: all 0.5s ease;
}
.image.active {
  opacity: 1;
}

.locker {
  outline: 1px solid #cdcdcd;
  outline-offset: -1px;
  position: relative;
  display: grid;
  grid-template-columns: [full-start] minmax(4.2rem, 1fr) [center-start] repeat(12, [col-start] minmax(min-content, 8rem) [col-end]) [center-end] minmax(4.2rem, 1fr) [full-end];
}
.locker__image {
  position: relative;
  grid-column: col-start 2/col-end 6;
}
.locker__image img {
  width: auto;
  height: 70vh;
  position: absolute;
  transition: all 1s ease;
}
.locker__container {
  position: sticky;
  position: -webkit-sticky;
  top: 0;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.locker__content {
  grid-column: col-start 8/center-end;
}
.locker__section {
  height: 100vh;
  display: flex;
  justify-content: center;
  flex-direction: column;
  border-top: 1px solid #cdcdcd;
}
.locker__section:first-child {
  border: none;
}
.locker__section p {
  width: 70%;
}

#message {
  position: fixed;
  top: 20px;
  left: 20px;
  background-color: white;
  height: auto;
  padding: 10px 20px;
  z-index: 900;
}