JSFiddle - React, Tailwind, and code Playground

HTML

<!-- outermost table -->
<table id="index">
    <thead>
        <tr>
            <td height="20px" class="brand">DemoDashboard</td>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>
                <!-- the table that holds all the widget rows and columns -->
                <table class="widgets-container">
                    <tbody>
                        <tr>
                            <td class="widget-holder" rowspan="1" colspan="1">
                                <table class="widget">
                                    <tbody>
                                        <tr id="trtitlewidget11">
                                            <td id="titlewidget11" class="widget-header">
                                                 <h3>Accident Claims Outstanding</h3>

                                            </td>
                                        </tr>
                                        <tr>
                                            <td class="widget-content" id="widget11">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consequuntur, soluta, laborum. Minima totam voluptatem veniam cupiditate ea vero expedita aspernatur deserunt aliquam quasi. Quae adipisci voluptatibus, dignissimos, sint laboriosam similique explicabo nobis quod, dolorem iusto harum blanditiis itaque laborum veniam eaque officiis quos quisquam accusamus nam. Esse vitae hic, illum!</td>
                                        </tr>
                                    </tbody>
                                </table>
                            </td>
                            <td class="widget-holder" rowspan="1" colspan="1">
                                <table class="widget">
                                    <tbody>
                                        <tr id="trtitlewidget12">
                                            <td id="titlewidget12" class="widget-header">
                                                 <h3>Disabled...

CSS

table#index {
    position: absolute;
    border-collapse: collapse;
    width: 100%;
    height: 100%;
    background-color: #ff0;
}
table#index td, table#index tr {
    vertical-align: top;
}
table#index > td {
    padding: 0;
}
table#index table.widgets-container {
    border-collapse: separate;
    border-spacing: 10px;
    width: 100%;
}
table#index table.widgets-container td.widget-holder {
    vertical-align: top;
    padding: 0;
    margin: 0;
}
/*------------------------------------------------------------------
[ Widget ]
*/
 table.widget {
    width: 100%;
    height: 100%;
    border-collapse: collapse;
    position: relative;
}
table.widget .widget-header {
    color: #333333;
    background-color: #f5f5f5;
    border: 1px solid #ddd;
    height: 25px;
    border-top-right-radius: 3px;
    border-top-left-radius: 3px;
    cursor: pointer;
}
table.widget .widget-header h3 {
    font-size: 10pt;
    font-family: Verdana, Arial, sans-serif;
    font-weight: normal;
    color: #525252;
    text-align: left;
}
table.widget .widget-header[class^="icon-"], table.widget .widget-header .widget-header[class*=" icon-"] {
    display: inline-block;
    margin-left: 13px;
    margin-right: -2px;
    font-size: 12px;
    color: #555;
    vertical-align: middle;
}
table.widget .widget-content {
    border-radius: 3px;
    background: #FFF;
    border-left: 1px solid #D5D5D5;
    border-right: 1px solid #D5D5D5;
    border-bottom: 1px solid #D5D5D5;
    border-top: 0 none;
    vertical-align: top;
    padding: 15px;
}
table.widget .widget-header + .widget-content {
    border-top: none;
    border-top-left-radius: 0;
    border-top-right-radius: 0;
}
table.widget .widget-nopad .widget-content {
    padding: 0;
}
table.widget .toggleIcon {
    float: left;
    width: 11px;
    height: 11px;
    margin: 2px 8px 0 4px;
    font-family:'Glyphicons Halflings';
    font-size: 16px;
    color: #323232;
    font-weight: 700;
}
table.widget .toggleIcon.toggleIconMinus:before...

JavaScript

var fitHeight = function() {
        $("table.widget").each(function() {
            $(this).removeAttr("style");
        });
        $("table.widget").each(function() {
            $(this).height($(this).parent().height());
        });
    }
    
    $(window).resize(fitHeight);
    $(document).ready(fitHeight);