JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
<!-- Select2 -->
<link href="https://cdn.jsdelivr.net/npm/select2@4.1.0-rc.0/dist/css/select2.min.css" rel="stylesheet" />
<!-- Daterangepicker -->
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/daterangepicker/daterangepicker.css" />
<link rel="stylesheet" href="./style2.css">

<link rel="stylesheet" href="https://cdn.datatables.net/1.11.3/css/jquery.dataTables.min.css">
<link rel="stylesheet" href="https://cdn.datatables.net/fixedheader/3.2.0/css/fixedHeader.dataTables.min.css">


<head>
</head>
<body>

   <div class="main">  
      <div class="container-main1" style="backcolor:#222">
         <div class="container">
				 
            <h1>Accordion/Select2</h1>
            <div class="container__accordion">
               <ul class="accordion">
                  <li class="accordion__item">
                     <!-- Accordion 1 -->
                     <div class="accordion__item__head">
                        <button class="accordion">SELECT1</button>
                     </div>
                     <div class="accordion__item__body">
                        <div class="accordion-content accordion-select">
                           <select class="js-example-basic-single1" name="state">
                              <option value="AL">Alabama</option>
                              <option value="WY">Wyoming</option>
                              <option value="AL">Alabama</option>
                              <option value="WY">Wyoming</option>
                              <option value="AL">Alabama</option>
                              <option value="WY">Wyoming</option>
                              <option value="AL">Alabama</option>
                              <option value="WY">Wyoming</option>
                              <option value="AL">Alabama</option>
                              <option...

CSS

body{
  margin: 0;
}
.container-main {
 /*height: 100vh;*/
 background: #EFF0F1;
 overflow: auto;
}

/*.container {
 width: 80%;
 max-width: 600px;
 margin: 50px auto;
}*/

button.accordion {
 width: 100%;
 background-color: whitesmoke;
 border: none;
 outline: none;
 text-align: left;
 padding: 15px 20px;
 font-size: 18px;
 color: #333;
 cursor: pointer;
 transition: background-color 0.2s linear;
}

button.accordion:after {
 font-family: FontAwesome;
 content: "\f150";
 font-family: "fontawesome";
 font-size: 18px;
 float: right;
}

button.accordion.is-open:after {
 content: "\f151";
}

button.accordion:hover,
button.accordion.is-open {
 background-color: #ddd;
}


.select2-container{
  position: relative!important;
  top:0!important;
  left: 0!important;
}
.select2-dropdown{
  position: relative!important;
}
/*accordion*/
.container__accordion {
  display: flex;
  align-items: center;
  justify-content: center;
}

.accordion {
  list-style: none;
  width: 100%;
  padding: 0;
  margin: 0 auto;
}
.accordion__item {
  border: 1px solid #f2f2f2;
  transition: all 0.2s linear;
}
.accordion__item.open {
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}
.accordion__item__head {
}

.accordion__item__head {border: none;outline: none;text-align: left;font-size: 18px;color: #333;cursor: pointer;transition: background-color 0.2s linear;}
.accordion__item__head h2 {
  font-size: 18px;
  font-weight: 300;
  font-family: Arial;
  text-transform: uppercase;
  margin: 0;
}
.accordion__item__head i {
  transition: transform 0.3s linear;
}
.accordion__item.open .accordion__item__head i {
  transform: rotate(-180deg);
}

.accordion__item__body {
  overflow: hidden;
  height: 0;
}
.accordion__item.open .accordion__item__body {
  padding: 1rem;
  height: auto;
}
.accordion__item__body > *:not(:first-child) {
  margin-top: 0.8rem;
}
.accordion__item__body p {
  font-size: 0.9rem;
  line-height: 1.3;
}
.accordion__item__head h2:after {
  content: "\f150";
  font-family: "fontawesome";
 ...

JavaScript

$(document).ready(function() {
    $('.js-example-basic-single1').select2({
      dropdownParent: $('#myModal'),
    });
    $('.js-example-basic-single2').select2({
      dropdownParent: $('#myModal2'),
    });
	
    $('#example').DataTable( {
        fixedHeader: true
    } );
	
	
    $('input[name="daterange"]').daterangepicker({
     opens: 'left',
     drops: 'down',
     parentEl: "#divChooseDossier",
     showDropdowns: true,
	});
});


// BD custom js
const accordion_items_elms = document.querySelectorAll('.accordion .accordion__item');

accordion_items_elms.forEach(accordionItem => {

  accordionItem.querySelector('.accordion__item__head').addEventListener('click', (e) => {
    accordionItem.classList.toggle('open');
  });
});