<div class="bg"></div>
<div class="c-scroll-icon">
  <div class="c-scroll-icon-line-mask"><div class="c-scroll-icon-line"></div></div>
  <div class="c-scroll-icon-triangle">
    <div class="c-scroll-icon-triangle-mask first"><div class="c-scroll-icon-triangle-line first"></div></div>
    <div class="c-scroll-icon-triangle-mask right"><div class="c-scroll-icon-triangle-line right"></div></div>
    <div class="c-scroll-icon-triangle-mask left"><div class="c-scroll-icon-triangle-line left"></div></div>
    <div class="c-scroll-icon-triangle-mask last"><div class="c-scroll-icon-triangle-line last"></div></div>
  </div>
</div>

*, *::before, *::after {
    box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html, body {
  height: 100%;
  background-color: #1d1f20;
}
@color: #fff;
.bg {
      background: url(https://vignette.wikia.nocookie.net/thehungergames/images/3/31/Cassandra_Oracion.jpg) no-repeat center;
    background-size: cover;
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  filter: blur(7px);
}
.c-scroll-icon {
  width: 21px;
  height: 100px;
  transform: translate3d(-50%, 0%, 0);
  position: absolute;
  left: 50%;
  bottom: 100px;
  backface-visibility: hidden;
  .c-scroll-icon-line-mask {
    position: relative;
    overflow: hidden;
    width: 21px;
    height: 100px;
    margin: 0 auto;
  }
  .c-scroll-icon-line {
    position: absolute;
    display: inline-block;
    width: 1px;
    height: 150px;
    border-left: 1px solid @color;
    top: -150px;
    left: 10px;
    animation: scroll-line 3s infinite;
    transition: all cubic-bezier(0.785, 0.135, 0.15, 0.86);
  }
}


@keyframes scroll-line {
    0% {
        transform: translate3d(0, 0, 0)
    }
    40% {
        transform: translate3d(0, 185px, 0)
    }
    75% {
        transform: translate3d(0, 175px, 0)
    }
    100% {
        transform: translate3d(0, 280px, 0)
    }
}

.c-scroll-icon-triangle {
    position: relative;
    width: 20px;
    height: 30px;
    margin: -10px auto 0;
    animation: triangle-bounce 3s infinite;
}

.c-scroll-icon-triangle-mask {
    position: absolute
}

.c-scroll-icon-triangle-mask.first {
    width: 40px;
    height: 5px;
    right: 0;
    overflow: hidden
}

.c-scroll-icon-triangle-mask.right {
    width: 10px;
    height: 30px;
    overflow: hidden;
    right: 0
}

.c-scroll-icon-triangle-mask.left {
    width: 10px;
    height: 30px;
    overflow: hidden;
    left: 1
}

.c-scroll-icon-triangle-mask.last {
    width: 40px;
    height: 5px;
    overflow: hidden
}

.c-scroll-icon-triangle-line {
    position: absolute
}

.c-scroll-icon-triangle-line.first {
    border-bottom: 1px solid @color;
    width: 30px;
    right: 0;
    animation: triangle-first 3s infinite;
    transition: all 600ms cubic-bezier(0.785, 0.135, 0.15, 0.86)
}

.c-scroll-icon-triangle-line.right {
    border-left: 1px solid @color;
    height: 44px;
    transform: rotate(-163deg);
    right: 5px;
    top: -6px;
    animation: triangle-right 3s infinite;
    transition: all 600ms cubic-bezier(0.785, 0.135, 0.15, 0.86)
}

.c-scroll-icon-triangle-line.left {
    border-left: 1px solid @color;
    height: 40px;
    transform: rotate(163deg);
    left: 5px;
    top: -3px;
    animation: triangle-left 3s infinite;
    transition: all 0.6s cubic-bezier(0.785, 0.135, 0.15, 0.86);
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden
}

.c-scroll-icon-triangle-line.last {
    border-bottom: 1px solid @color;
    width: 120px;
    left: 0;
    animation: triangle-last 3s infinite;
    transition: all 600ms cubic-bezier(0.785, 0.135, 0.15, 0.86)
}

@keyframes triangle-bounce {
    0% {
        transform: translate3d(0, -5px, 0)
    }
    50% {
        transform: translate3d(0, 5px, 0)
    }
    100% {
        transform: translate3d(0, -5px, 0)
    }
}

@keyframes triangle-first {
    0%,
    20% {
        transform: translate3d(-40px, 0, 0)
    }
    30%,
    80% {
        transform: translate3d(10px, 0, 0)
    }
    85%,
    100% {
        transform: translate3d(30px, 0, 0)
    }
}

@keyframes triangle-right {
    0%,
    25% {
        transform: rotate(-163deg) translate3d(0, 40px, 0)
    }
    40%,
    84% {
        transform: rotate(-163deg) translate3d(0, 0, 0)
    }
    90%,
    100% {
        transform: rotate(-163deg) translate3d(0, -37px, 0)
    }
}

@keyframes triangle-left {
    0%,
    33% {
        transform: rotate(163deg) translate3d(0, -34px, 0)
    }
    50%,
    88% {
        transform: rotate(163deg) translate3d(0, 0, 0)
    }
    95%,
    100% {
        transform: rotate(163deg) translate3d(0, 38px, 0)
    }
}

@keyframes triangle-last {
    0%,
    87.5% {
        transform: translate3d(-120px, 0, 0)
    }
    91% {
        transform: translate3d(-80px, 0, 0)
    }
    100% {
        transform: translate3d(45px, 0, 0)
    }
}