JSFiddle - React, Tailwind, and code Playground

HTML

<div class="dropdown">
  <label class="active" for="check"></label>
  <input type="checkbox" hidden id="check"/>
  <ul class="list">
  <li><input type="button" value="11111111" onclick="document.getElementsByClassName('active')[0].innerHTML = this.value;document.getElementById('check').checked = false;"/></li>
    <li><input type="button" value="2222222" onclick="document.getElementsByClassName('active')[0].innerHTML = this.value;document.getElementById('check').checked = false;"/></li>
    <li><input type="button" value="3333333" onclick="document.getElementsByClassName('active')[0].innerHTML = this.value;document.getElementById('check').checked = false;"/></li>
  </ul>
</div>

CSS

.dropdown {
  position: relative;
  font-size: 16px;
  color: #000;
  box-sizing: border-box;
  max-width: 350px;
}
.active {
  display: block;
  padding: 5px 10px;
  border: 1px solid #000;
  height: 30px;
  line-height: 30px;
}
.list {
  position: absolute;
  margin: 0 0 0 auto;
  list-style: none;
  padding: 0;
  border: 1px solid #f00;
  display: none;
  width: calc(100% - 2px);
}
#check:checked + .list {
  display: block;
}
.list li {
  border-bottom: 1px solid #f00;
}
.list li input {
  background: transparent;
  border: none;
  padding: 10px 5px;
  display: block;
  box-shadow: none;
  width: 100%;
  text-align: left;
}