Edit File: pum-admin-theme-editor.min.css
.pum-overlay .pum-popup-content,.pum-overlay .pum-popup-title,.pum-popup-overlay,.pum-popup-overlay .pum-popup-close,.pum-popup-overlay .pum-popup-close:active,.pum-popup-overlay .pum-popup-close:focus,.pum-popup-overlay .pum-popup-closeclose-popup:hover,.pum-popup-overlay .pum-popup-container{background:0 0;border:none;bottom:auto;clear:none;cursor:default;float:none;font-family:Arial,Helvetica,sans-serif;font-size:medium;font-style:normal;font-weight:400;height:auto;left:auto;letter-spacing:normal;line-height:normal;max-height:none;max-width:none;min-height:0;min-width:0;overflow:visible;position:static;right:auto;text-align:left;text-decoration:none;text-indent:0;text-transform:none;top:auto;visibility:visible;white-space:normal;width:auto;z-index:auto}.pum-popup-container,.pum-popup-container *,.pum-popup-container :after,.pum-popup-container :before,.pum-popup-container:after,.pum-popup-container:before{box-sizing:border-box}.pum-popup-content p{margin-top:0}#pum_theme_settings .inside{padding:0;margin:0}#pum_theme_settings .wp-picker-container{display:inline-block}#pum_theme_preview .inside{margin-top:0;padding:0;background:url(https://s.wordpress.com/mshots/v1/https://www.wordpress.org) center top/cover no-repeat}#pum_theme_preview .pum-theme-preview{padding:50px 20px;position:relative}#pum_theme_preview .pum-popup-close,#pum_theme_preview .pum-popup-container,#pum_theme_preview .pum-popup-content,#pum_theme_preview .pum-popup-overlay,#pum_theme_preview .pum-popup-title{cursor:pointer}.pum-theme-preview .pum-popup-overlay{position:absolute;display:block;width:100%;height:100%;top:0;left:0}.pum-theme-preview .pum-desc,.pum-theme-preview .pum-popup-container{display:block;position:relative;width:95%;max-width:400px;margin:0 auto;font-size:16px;z-index:99}.pum-theme-preview .pum-desc .pum-popup-close,.pum-theme-preview .pum-popup-container .pum-popup-close{text-decoration:none;text-align:center;line-height:1;position:absolute;cursor:pointer;min-width:1em;z-index:9999999;background-color:transparent}.pum-theme-preview .pum-desc{box-sizing:border-box;margin:10px auto 0;background-color:#fff;border:1px solid;box-shadow:0 2px 2px;padding:.75em;font-size:11px;z-index:10}.pum-theme-preview .pum-desc .dashicons{font-size:16px;width:16px;height:16px}