JSFiddle - React, Tailwind, and code Playground

HTML

<div class="modalWindow tb-map-undraggable"><p class="mw-titleBlock"><span class="mw-tb-title">Это длинное название 123456 трололо qwertyuiop[]asd апро лджжэ 1qaz2wsx 3увс4к п 6рн67о76о76шл87ше6</span><span class="mw-tb-close"></span></p><div class="mw-contents">Содержимое
<br/><br/><br/><br/>ввв<br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/>Нижняя часть содержимого</div></div>

CSS

div.modalWindow
{
    background-color: white;
    color: #555;
    border: 1px solid #aaa;
    box-shadow: 0 0 15px rgba(0,0,0,0.2);
    border-radius: 5px;
    position: absolute;
    top: 50px;
    left: 50px;
    z-index: 4;
}
div.modalWindow > p.mw-titleBlock
{ 
    cursor: move;
    padding: 4px;
    background-color: #f4f4f4;
    border-radius: 5px 5px 0 0;
    font-weight: bold;
    font-size: 11pt;
}
div.modalWindow span.mw-tb-title
{
    overflow-x: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
div.modalWindow span.mw-tb-close
{
    float: right;
    width: 16px;
    height: 16px;
    margin-top: 2px;
    cursor: pointer;
    background: url(/images/close.png);
}
div.modalWindow span.mw-tb-close:hover { background-position: 0 -16px; }
div.modalWindow span.mw-tb-close:active { background-position: 0 -32px; }
div.modalWindow > div.mw-contents
{
    resize: both;
    overflow: auto;
    min-width: 400px;
    min-height: 400px;
    max-height: 92%;
    border-radius: 5px;
    padding: 5px;
    border: 1px solid #000;
}