html, body {
  padding: 0;
  margin: 0;
}

.pin-spacer {
  display: block !important; /* default */
}

.about_container {
  position: relative;
  height: 100vh;
  overflow: hidden;
}

.trigger {
  padding: 0 5% 0 12%;
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
  height: 100vh;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  position: absolute;
  inset: 0; /* top, right, bottom, left: 0 */
  width: 100%;
  opacity: 0;
  z-index: 1;
  -webkit-transition: 1s;
  transition: 1s;
}

#frist {
  opacity: 1;
  z-index: 20;
}

#end {
  opacity: 0;
  z-index: 1;
}

.trigger.is-active {
  visibility: inherit;
  opacity: 1;
  z-index: 20;
  background: #fff;
}

.trigger:not(.is-active) {
  z-index: 1;
}