JSFiddle - React, Tailwind, and code Playground

HTML

<div class="slidebox">
    <div class="slidebox-close">x</div>
    <div class="slidebox-header"></div>
    <div class="slidebox-content">
        <div>Будьте в курсе акций, скидок
и выгодных предложений
        </div>
        <div>
            <input>
            <button>Подписаться</button>
            </div>
    </div>
    <div class="slidebox-footer">Подписаться!</div>
</div>

CSS

.slidebox {
    position: fixed;
    bottom:0;
    left: 50%;
    margin-left: -150px;
    width:302px;
    height:34px;
    overflow:hidden;
    box-shadow: 0 0 5px rgba(0,0,0,0.3);
    background-color: transparent;
    border:1px solid transparent;
    border-radius: 9px 9px 0 0;
}
.slidebox-header {
    position:absolute;
    left:0;
    top:0;
    width:300px;
    background:green;
    border:1px solid green;
    border-radius: 9px 9px 0 0;
    height:17px;
    z-index:100;
}
.slidebox-footer {
    position:absolute;
    width:300px;
    left:0;
    bottom:0;
    background:green;
    border:1px solid green;
    height:23px;
    cursor:pointer;
    color:#fff;
    text-align:center;
    z-index:102;
}
.slidebox-content {
    background:#ccc;
    height:100%;
}
.slidebox-content div {padding:20px 15px 0;}
.slidebox-close {
    position:absolute;
    right:0;
    top:0;
    width:20px;
    height:20px;
    z-index:101;
    cursor:pointer;
    text-align:center;
    color:#fff;
    font-weight:bold;
}

JavaScript

$.fn.switch = function(firstFunc, secondFunc) {
    $(this).on('click', function(e) {
        if ($(this).data('switch')) {
            secondFunc.call(this, e);
            $(this).data({'switch': false});
        }        
        else {
            firstFunc.call(this, e);
            $(this).data({'switch': true});
        }        
    });
 
    return $(this);
};
$(window).ready(function(){
   $('.slidebox-footer').switch(function(){
       $(this).parent().animate({height:150});}
   ,function(){
       $(this).parent().animate({height:34});
   });
   $('.slidebox-close').click(function(){
       $(this).parent().animate({height:34});
   });
});