dropdown style css code example

Example 1: css dropdown

<style>
.dropdown {
  position: relative;
  display: inline-block;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
  padding: 12px 16px;
  z-index: 1;
}

.dropdown:hover .dropdown-content {
  display: block;
}
</style>

<div class="dropdown">
  <span>Mouse over me</span>
  <div class="dropdown-content">
    <p>Hello World!</p>
  </div>
</div>

Example 2: change option tag css

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />
<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap-select.min.css" rel="stylesheet" />
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap-select.min.js"></script>

<select class="selectpicker">
  <option>Mustard</option>
  <option class="special">Ketchup</option>
  <option style="background: #5cb85c; color: #fff;">Relish</option>
</select>