<div class="arrow-up"></div>

.arrow-up {
  width: 36px;
  height: 38px;
  background: #eb5c58;
  position: relative;
  border-radius: 2px;
}

.arrow-up:after,
.arrow-up:before {
  content: "";
  display: block;
  position: absolute;
  left: 6px;
  top: 6px;
  width: 0;
  height: 0;
  border-left: 12px solid transparent;
  border-right: 12px solid transparent;
  border-bottom: 12px solid #fff;
}

.arrow-up:after {
  top: 18px;
  border-left-color: #fff;
  border-right-color: #fff;
  border-bottom-color: #eb5c58;
}

.arrow-up:hover {
  background: red
}

.arrow-up:hover:after {
  border-bottom-color: red;
}