<div class="cp_timeline03">
  <div class="timeline_group">
    <span class="time_year">2018</span>
    <div class="timeline_item">
      <div class="time">
        <span class="time_day">22</span>
        <span class="time_month">Feb</span>
      </div>
      <div class="desc">
        <p class="flag">タイトル</p>
        内容
      </div>
    </div>
    <div class="timeline_item">
      <div class="time">
        <span class="time_day">10</span>
        <span class="time_month">Sept</span>
      </div>
      <div class="desc">
        <p class="flag">タイトル</p>
        内容
      </div>
    </div>
  </div>
  <div class="timeline_group">
    <span class="time_year">2017</span>
    <div class="timeline_item">
      <div class="time">
        <span class="time_day">1</span>
        <span class="time_month">Jul</span>
      </div>
      <div class="desc">
        <p class="flag">タイトル</p>
        内容
      </div>
    </div>
  </div>
  <div class="timeline_group">
    <span class="time_year">2016</span>
    <div class="timeline_item">
      <div class="time">
        <span class="time_day">14</span>
        <span class="time_month">Aug</span>
      </div>
      <div class="desc">
        <p class="flag">タイトル</p>
        内容
      </div>
    </div>
  </div>
</div>

.cp_timeline03 {
  position: relative;
  margin: 3em auto;
}
.cp_timeline03:before {
  position: absolute;
  content: '';
  top: 0;
  left: 30px;
  width: 4px;
  height: 100%;
  background-color: #006064;
}
.cp_timeline03 .timeline_group {
  position: relative;
  padding-top: 55px;
}
.cp_timeline03 .timeline_group:not(:first-of-type) {
  margin-top: 4rem;
}
.cp_timeline03 .time_year {
  position: absolute;
  top: 0;
  left: 0;
  padding: 0.5rem 1.5rem;
  color: #fff;
  background-color: #00838F;
  width: 100%;
  box-sizing: border-box;
}
.cp_timeline03 .timeline_item {
  margin-bottom: 1em;
  position: relative;
  padding-left: 80px;
  display: flex;
  align-items: center;
}
.cp_timeline03 .timeline_item:not(:last-of-type) {
  margin-bottom: 2em;
}
.cp_timeline03 .timeline_item:before {
  position: absolute;
  content: '';
  left: 0;
  width: 100%;
  height: 3px;
  z-index: -1;
  background-color: #006064;
}
.cp_timeline03 .time {
  position: absolute;
  top: 50%;
  left: 0;
  min-width: 45px;
  min-height: 45px;
  padding: 0.5em 0.5em;
  margin-top: -33px;
  text-align: center;
  color: #fff;
  background-color: #26C6DA;
  border-radius: 50%;
}
.cp_timeline03 .time_day {
  font-size: 1em;
  font-weight: 700;
  display: block;
}
.cp_timeline03 .time_month {
  font-size: 0.8em;
  display: block;
  text-transform: uppercase;
}
.cp_timeline03 .desc {
  padding: 0.5em 1em;
  width: 100%;
  border-left: 3px solid #26C6DA;
  border-radius: 2px;
  background-color: #fff;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.2);
  font-size: 0.9em;
}
.cp_timeline03 .desc .flag {
  font-size: 1.2em;
  font-weight: bold;
  margin: 0;
  padding: 0;
  padding-bottom: 0.3em;
}
@media only screen and (max-width: 767px) {
  .cp_timeline03:before {
    left: 0;
  }
  .cp_timeline03 .timeline_group {
    padding-top: 40px;
  }
  .cp_timeline03 .timeline_item {
    padding-top: 60px;
    padding-left: 20px;
  }
  .cp_timeline03 .timeline_item:before {
    top: 90px;
  }
  .cp_timeline03 .time {
    top: 40px;
    border-radius: 0 20px 20px 0;
    min-height: 1em;
  }
  .cp_timeline03 .time_day,
  .cp_timeline03 .time_month {
    display: inline-block;
  }
  .cp_timeline03 .desc {
    font-size: 0.8em;
  }
}