cssだけでselectとシンプルな矢印

コード

html

<div class="selectWrap">
    <select class="select" name="" id="">
        <option value="">001</option>
        <option value="">002</option>
        <option value="">003</option>
    </select>
</div>

css

.selectWrap{
  width: 100%;
  position: relative;
  display: inline-block;
}
.selectWrap::after {
  content: '';
  width: 6px;
  height: 6px;
  border: 0px;
  border-bottom: solid 2px #b4b3b3;
  border-right: solid 2px #b4b3b3;
  -ms-transform: rotate(45deg);
  -webkit-transform: rotate(45deg);
  transform: rotate(45deg);
  position: absolute;
  top: 50%;
  right: 10px;
  margin-top: -4px;
}
.select {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  width: 100%;
  height: 40px;
  background: transparent;
  position: relative;
  z-index: 1;
  padding: 0 40px 0 10px;
  border: 1px solid #b4b3b3;
  border-radius: 2px;
}
select::-ms-expand {
    display: none;
}