JSFiddle - React, Tailwind, and code Playground

HTML

<div id="popup" data-role="popup" data-history="false" data-dismissible="true" class="ui-content active floateddiv options options2 ui-popup ui-body-inherit ui-overlay-shadow ui-corner-all">
  <div data-role="header" data-theme="a"><h2 class="dialogTitle"><span>Title of the Dialog</span></h2></div>
  <div class="dialogOptions">
    <div class="ui-radio">
      <label class="ui-btn ui-corner-all ui-btn-inherit ui-btn-icon-left ui-radio-off">
        <img src="https://placehold.co/400x600" class="item">
      </label>
    </div>
    <div class="ui-radio">
      <label class="ui-btn ui-corner-all ui-btn-inherit ui-btn-icon-left ui-radio-on">
        <img src="https://placehold.co/400x600" class="item">
      </label>
    </div>
    </div>
  <div class="okBtn">
    <div class="ui-btn ui-input-btn ui-btn-a ui-corner-all ui-shadow ui-btn-inline ui-icon-check ui-btn-icon-left"><input class="button" data-inline="true" data-theme="a" type="button" value="OK" id="btn_ok">
    </div>
  </div>
</div>

CSS

*, *::before, *::after {
    box-sizing: border-box;
}

#popup {
    font-size: 1em;
    font-family: sans-serif;
    -webkit-text-size-adjust: 100%;
    -webkit-tap-highlight-color: rgba(0,0,0,0);
    cursor: auto;
    line-height: 1.3;
    border-radius: .3125em;
    background-clip: padding-box;
    box-shadow: 0 0 12px rgba(0,0,0,.6);
    padding: 1em;
    position: relative;
    background-color: #fff;
    border-color: #ddd;
    color: #333;
    text-shadow: 0 1px 0 #f3f3f3;
    border-width: 1px;
    border-style: solid;
    overflow: visible;
    flex-direction: column;
    text-align: center;
    max-width: 1379px;
    max-height: 638px;

    height: 600px;
    display: grid;
}

#popup .dialogOptions {
    display: flex;
    overflow: auto; 
    height: 100%;
    /* position: relative; */
}

.ui-checkbox, .ui-radio {
    margin: .5em 0;
    position: relative;
}

.ui-radio .ui-btn {
    -webkit-text-size-adjust: 100%;
    -webkit-tap-highlight-color: rgba(0,0,0,0);
    box-sizing: border-box;
    line-height: 1.3;
    font-family: sans-serif;
    text-decoration: none!important;
    background-clip: padding-box;
    padding: .7em 1em;
    position: relative;
    text-overflow: ellipsis;
    overflow: hidden;
    cursor: pointer;
    user-select: none;
    padding-left: 2.5em;
    font-size: 16px;
    font-weight: 700;
    border-width: 1px;
    border-style: solid;
    display: block;
    border-radius: .3125em;
    background-color: #f6f6f6;
    border-color: #ddd;
    color: #333;
    text-shadow: 0 1px 0 #f3f3f3;
    margin: 0;
    text-align: left;
    white-space: normal;
    z-index: 2;
    max-width: max-content;
    height: 100%;
}

#popup img {
    height: 100%;
    max-width: max-content;
}
#game img, #popup img {
    width: 100%;
    vertical-align: top;
}

.okBtn {
  text-align: center;
}