JSFiddle - React, Tailwind, and code Playground

HTML

<div id='window'>
  <div id='container'>
    <div id='content'>
      <span class='snack_msg'>New message arrived</span>
      <span class='snack_btn' onclick='open_snack_message()'>open</span>
    </div>
  </div>
</div>

CSS

body
{
  font-family: sans-serif;
}

#window
{
    background-color: black;
    color: white;
    display: flex;
    flex-direction: column;
    opacity: 1;
    left: 50%;
    bottom: 0px;
    position: fixed;
    width: auto;
    height: auto;
    min-width: 600px;
    min-height: auto;
    max-width: 80vw;
    max-height: 80vh;
    transform: translateX(-50%);
    outline: 0px;
    cursor: default;
    z-index: 5000002;
    zoom: 1;  
}

#container
{
    overflow-y: auto;
    overflow-x: hidden;
    border: none;
    outline: 0;
    margin: 0;
    flex-grow: 1;  
}

#content
{
    font-size: 22px;
    text-align: center;
    overflow-wrap: break-word;
    padding-top: 1.6em;
    padding-bottom: 1.6em;
    padding-left: 1.6em;
    padding-right: 1.6em;  
}

.snack_msg
{
    padding-right: 200px;
    float:left;
}

.snack_btn
{
    color:#5fce49;
    text-transform: uppercase;
    letter-spacing:3px;
    cursor:pointer;
    float:right;
}