.main-timeline{
  overflow: hidden;
  position: relative;
}

.main-timeline:before{
  content: "";
  width: 5px;
  height: 70%;
  background:#333;
  position: absolute;
  top: 70px;
  left: 50%;
  transform: translateX(-50%);
}

.main-timeline .timeline{
  width: 50%;
  padding-left: 100px;
  float: right;
  position: relative;
}

.main-timeline .timeline:before{
  content: "";
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: #fff;
  border: 5px solid #333;
  position: absolute;
  top: 50%;
  left: -10px;
  transform: translateY(-50%);
}

.main-timeline .timeline-content{
  display: block;
  padding-left: 150px;
  position: relative;
}

.main-timeline .timeline-content:before{
  content: "";
  width: 90px;
  height: 10px;
  border-top: 7px dotted #333;
  position: absolute;
  top: 50%;
  left: -92px;
  transform: translateY(-50%);
}

.main-timeline .year{
  display: inline-block;
  width: 120px;
  height: 120px;
  line-height: 100px;
  border-radius: 50%;
  border: 10px solid #f54957;
  font-size: 12px;
  color: #f54957;
  text-align: center;
  box-shadow: inset 0 0 10px rgba(0,0,0,0.4);
  position: absolute;
  top: calc(50% - 90px);
  left: 0;
}

.main-timeline .year:before{
  content: "";
  border-left: 20px solid #f54957;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  position: absolute;
  bottom: -13px;
  right: 0;
  transform: rotate(45deg);
}

.main-timeline .inner-content{ padding: 20px 0; }

.main-timeline .title{
  font-size: 24px;
  font-weight: 600;
  color: #f54957;
  text-transform: uppercase;
  margin: 0 0 5px 0;
}

.main-timeline .description{
  font-size: 14px;
  color: #6f6f6f;
  margin: 0 0 5px 0;
}

.main-timeline .timeline:nth-child(2n){ padding: 0 100px 0 0; }

.main-timeline .timeline:nth-child(2n):before,
.main-timeline .timeline:nth-child(2n) .timeline-content:before,
.main-timeline .timeline:nth-child(2n) .year{
  left: auto;
  right: -10px;
}

.main-timeline .timeline:nth-child(2n) .timeline-content{ padding: 0 150px 0 0; }

.main-timeline .timeline:nth-child(2n) .timeline-content:before{ right: -92px; }

.main-timeline .timeline:nth-child(2n) .year{ right: 0; }

.main-timeline .timeline:nth-child(2n) .year:before{
  right: auto;
  left: 0;
  border-left: none;
  border-right: 20px solid #f54957;
  transform: rotate(-45deg);
}

.main-timeline .timeline:nth-child(2){ margin-top: 110px; }

.main-timeline .timeline:nth-child(odd){ margin: -110px 0 0 0; }

.main-timeline .timeline:nth-child(even){ margin-bottom: 80px; }

.main-timeline .timeline:first-child,
.main-timeline .timeline:last-child:nth-child(even){ margin: 0; }

.main-timeline .timeline:nth-child(2n) .year{
  border-color: #1ebad0;
  color: #1ebad0;
}

.main-timeline .timeline:nth-child(2) .year:before{ border-right-color: #1ebad0; }

.main-timeline .timeline:nth-child(2n) .title{ color: #1ebad0; }

.main-timeline .timeline:nth-child(3n) .year{
  border-color: #7cba01;
  color: #7cba01;
}

.main-timeline .timeline:nth-child(3) .year:before{ border-left-color: #7cba01; }

.main-timeline .timeline:nth-child(3n) .title{ color: #7cba01; }

.main-timeline .timeline:nth-child(4n) .year{
  border-color: #f8781f;
  color: #f8781f;
}

.main-timeline .timeline:nth-child(4) .year:before{ border-right-color: #f8781f; }

.main-timeline .timeline:nth-child(4n) .title{ color: #f8781f; }

@media only screen and (max-width: 1200px){
  .main-timeline .year{
      top: 50%;
      transform: translateY(-50%);
  }
}

@media only screen and (max-width: 990px){
  .main-timeline .timeline{ padding-left: 75px; }
  .main-timeline .timeline:nth-child(2n){ padding: 0 75px 0 0; }
  .main-timeline .timeline-content{ padding-left: 130px; }
  .main-timeline .timeline:nth-child(2n) .timeline-content{ padding: 0 130px 0 0; }
  .main-timeline .timeline-content:before{
      width: 68px;
      left: -68px;
  }
  .main-timeline .timeline:nth-child(2n) .timeline-content:before{ right: -68px; }
}

@media only screen and (max-width: 767px){
  .main-timeline{ overflow: visible; }
  .main-timeline:before{
      height: 100%;
      top: 0;
      left: 0;
      transform: translateX(0);
  }
  .main-timeline .timeline:before,
  .main-timeline .timeline:nth-child(2n):before{
      top: 60px;
      left: -9px;
      transform: translateX(0);
  }
  .main-timeline .timeline,
  .main-timeline .timeline:nth-child(even),
  .main-timeline .timeline:nth-child(odd){
      width: 100%;
      float: none;
      text-align: center;
      padding: 0;
      margin: 0 0 10px 0;
  }
  .main-timeline .timeline-content,
  .main-timeline .timeline:nth-child(2n) .timeline-content{ padding: 0; }
  .main-timeline .timeline-content:before,
  .main-timeline .timeline:nth-child(2n) .timeline-content:before{ display: none; }
  .main-timeline .year,
  .main-timeline .timeline:nth-child(2n) .year{
      position: relative;
      transform: translateY(0);
  }
  .main-timeline .year:before,
  .main-timeline .timeline:nth-child(2n) .year:before{
      border: none;
      border-right: 20px solid #f54957;
      border-top: 10px solid transparent;
      border-bottom: 10px solid transparent;
      top: 50%;
      left: -23px;
      bottom: auto;
      right: auto;
      transform: rotate(0);
  }
  .main-timeline .timeline:nth-child(2n) .year:before{ border-right-color: #1ebad0; }
  .main-timeline .timeline:nth-child(3n) .year:before{ border-right-color: #7cba01; }
  .main-timeline .timeline:nth-child(4n) .year:before{ border-right-color: #f8781f; }
  .main-timeline .inner-content{ padding: 10px; }
}