JSFiddle - React, Tailwind, and code Playground

HTML

<ul id='menu'>   
                <li><a href='#' class='drop'>lyže</a> 
      
                <div class='dropdown'>
                    <div class='content'>
                    
                    <fieldset>
                    <legend><b>vyber lyže</b></legend>
                            <table class='equipment_find_tab'>
                            <tr>
                                <td class='left_content_tab_td1'>IDN</td>
                                <td class='left_content_tab_td2'><input class='left_content_tab_text' type='text' name='equipmentIDN'/></td>
                            </tr>
                            <tr>
                                <td class='left_content_tab_td1'>velikost</td>
                                <td class='left_content_tab_td2'>
  
                                <select class='left_content_tab_combobox' name='equipmentSize'>
                                            ");
                                            include ('size_ski.php');
                                            echo ("
                                            </select>
                                            </td>
                            </tr>
                            <tr>
                                <td class='left_content_tab_td1'>rozteč vázání</td>
                                <td class='left_content_tab_td2'>
  
                                <select class='left_content_tab_combobox' name='equipmentSize'>
                                            ");
                                            include ('size_ski.php');
                                            echo ("
                                            </select>
                                            </td>
                            </tr>
                            <tr>
                                <td class='left_content_tab_td1'>popis</td>
                                <td class='left_content_tab_td2'><input...

CSS

#menu {  
    list-style:none;  
    width:auto; 
    margin-top: 0px; 
    padding:0; 
    background-color: #acdcdc;
    font: normal 1em Verdana; 
    
}  
  
#menu li {  
    float:left;  
    text-align:center;  
    position:relative;  
    padding: 5px 10px 5px 10px;     
    border:none;
    border-right: 1px solid #777777;    
}  
  
#menu li:hover{
    border-right: 1px solid #777777;  
    padding: 5px 10px 5px 10px;     
    background: #ffffff;  
}  
  
#menu li a {  
font: normal 1em Verdana;   
    color: #184848;  
    display:block;  
    outline:0;
    height: 17px;  
    text-decoration:none;   
}  
  
#menu li:hover a {  
    color:#184848;  
}  

/* Drop Down */  
  
  
.dropdown {
    font: normal 1em Verdana;
    color:#184848; 
    margin-left:17.5%;  
    float:left;  
    position:fixed;  
    left:-999em; /* Hides the drop down */
    margin-top: 5px;  
    text-align:left;  
    border-top:none;  
    background:#184848;
    border-left: solid 0px #184848;
    padding:0px 0px 0px 0px;
    
      
 
}

.dropdown .content {  
    height: auto;
    background-color: #ffffff;
    padding: 10px 10px 10px 10px;
    border-left: solid 5px #184848;
    font: normal 1em Verdana; 

 
}  

.dropdown {width: 43.5%;}  
  
#menu li:hover .dropdown{
    left:0;  
    top:auto;  
}

.dropdown:hover,.dropdown_hover {
    left:0;  
    top:auto;  
}  
  

.dropdown .left_content_tab_text{
    font: normal 1em Verdana;
    width: 100%;
    border: solid 1px #68a3a3;
    color: #3b6464;
    border-radius: 2px;
}

.dropdown .left_content_tab_combobox{
    font: normal 1em Verdana;
    width: 50%;
    border: solid 1px #68a3a3;
    color:#3b6464;
    border-radius: 2px;
}  

.dropdown .ok {
    text-align: center;
    vertical-align: middle;
    height: 4ex;
    width: 7em;
    display: block;
    color: #fff;
    text-decoration: none;
    background-color:#68a3a3 ;
    border: solid 1px #68a3a3;
    border-radius: 3px;
    font: normal 1em...

JavaScript

$('.dropdown > .left_content_tab_combobox ').focus(function() {
    $('#dropdown').addClass('dropdown_hover');
}).blur(function() {
    $('#dropdown').removeClass('dropdown_hover');
});