select2 themes code example
Example: select2 full width
<select class="js-example-responsive" style="width: 50%"></select>
<select class="js-example-responsive" multiple="multiple" style="width: 75%"></select>
<select class="js-example-responsive" style="width: 50%"></select>
<select class="js-example-responsive" multiple="multiple" style="width: 75%"></select>