<div class="site-content cf">
  <div class="boxed-group dangerzone">

    <h3>Account</h3>

    <div class="boxed-group-inner">
      <section>
        <h4>Delete this account</h4>

        <button href="#" class="btn btn-danger boxed-action" id="delete-account">Delete Account</button>
        <p>This action is permanent; think twice before proceeding!</p>

        <dialog id="confirm-delete" class="site-dialog">
          <header class="dialog-header">
            <h1>Please Confirm</h1>
          </header>
          <div class="dialog-content">
            <p>You are about to close your account. This action is irreversible. It will permanently delete your account along with its associated data. Are you sure you want to continue?</p>
          </div>
          <div class="btn-group cf">
            <button id="delete">Delete</button>
            <button id="cancel">Cancel</button>

          </div>
        </dialog>

      </section>
    </div>
  </div>
</div>
@gray-darker : #555;
@gray-dark : #999;
@gray : #ddd;
@gray-light : #f3f3f3;
@gray-lighter : #e6e9ed;
@body-bg : #f5f7fa;
@body-color : @gray-darker;
@header-bg : #196e76;
@heading-bg : #434a54;
@button-danger-bg : #c0392b;
html {
  box-sizing: border-box;
}

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

.cf:before,
.cf:after {
  display: table;
  content: ' ';
}

.cf:after {
  clear: both;
}

.cf {
  *zoom: 1;
}

body {
  font-family: 'Roboto', Arial, sans-serif;
  margin: 0;
  color: @body-color;
  background-color: @body-bg;
}

img {
  max-width: 100%;
  height: auto;
}

figure {
  margin: 0;
  padding: 10px;
  a {
    display: block;
  }
}

mark {
  padding: 0 5px;
  background-color: @gray;
}

.btn-danger {
  padding: 10px 15px;
  cursor: pointer;
  border: 1px solid darken(@button-danger-bg, 5%);
  border-radius: 3px;
  color: #fff;
  background-color: @button-danger-bg;
  &:hover {
    background-color: darken(@button-danger-bg, 5%);
  }
}

.site-header {
  text-align: center;
  background-color: @header-bg;
  h1, a {
    padding: 15px;
    text-transform: uppercase;
    color: #fff;
  }
  h1 {
    font-size: 18px;
    margin: 0;
  }
  a {
    font-size: 14px;
    font-weight: 300;
    display: block;
    text-decoration: none;
    background-color: darken(@header-bg, 10%);
  }
}

.boxed-group {
  width: 90%;
  max-width: 680px;
  margin-top: 50px;
  margin-right: auto;
  margin-left: auto;
  h3, h4 {
    font-weight: 400;
    margin: 0;
  }
  h3 {
    padding: 12px 20px;
    color: #fff;
    border-top-left-radius: 5px;
    border-top-right-radius: 5px;
    background-color: @heading-bg;
  }
  h4 {
    font-size: 18px;
    color: @gray-darker;
  }
  section {
    padding: 30px 20px;
    &:first-child {
      border-bottom: 1px solid @gray-lighter;
    }
    &:only-of-type,
    &:only-child {
      border-bottom: 0;
    }
  }
  .boxed-group-inner {
    font-size: 14px;
    font-weight: 300;
    color: #aaa;
    border-width: 0 1px 1px;
    border-style: solid;
    border-color: @gray-lighter;
    border-bottom-right-radius: 5px;
    border-bottom-left-radius: 5px;
    background-color: #fff;
  }
  .btn {
    float: right;
    margin-left: 20px;
  }
}
(function($) {
  'use strict';

  var $accountDelete = $('#delete-account'),
    $accountDeleteDialog = $('#confirm-delete');

  $accountDelete.on('click', function() {
    $accountDeleteDialog[0].showModal();
  });

  $('#cancel').on('click', function() {
    $accountDeleteDialog[0].close();
  });

})(jQuery);

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js