見本

HTML

<span class="arrow2"></span>
<span class="arrow2 arrow2-white"></span>
<span class="arrow2 arrow2-white arrow2-btm"></span>

CSS

.arrow2 {
  display: block;
  position: relative;
  width: 18px;
  height: 18px;
  border-radius: 50%;
}

.arrow2,
.arrow2::after {
  border: 1px solid #56b9bf;
}

@media print, screen and (min-width: 641px) { /* pc only */
  .arrow2,
  .arrow2::after {
    transition: .3s;
  }
}

.arrow2::after {
  content: "";
  display: block;
  position: absolute;
  top: 50%;
  left: 50%;
  width: 5px;
  height: 5px;
  border-width: 1px 1px 0 0;
  -webkit-transform: rotate(45deg);
          transform: rotate(45deg);
  margin-left: -3.7px;
  margin-top: -2.5px;
}

.arrow2.arrow2-white {
  border: none;
  background-color: #fff;
}

.arrow2.arrow2-white::after {
  border-color: #4a98a9;
}

.arrow2.arrow2-btm::after {
  -webkit-transform: rotate(135deg);
          transform: rotate(135deg);
  margin-left: -2.5px;
}