<div id="root"><h1>Lorem ipsum dolor sit amet consectetuer adipiscing 
elit</h1>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing 
elit. Aenean commodo ligula eget dolor. Aenean massa 
<strong>strong</strong>. Cum sociis natoque penatibus 
et magnis dis parturient montes, nascetur ridiculus 
mus. Donec quam felis, ultricies nec, pellentesque 
eu, pretium quis, sem. Nulla consequat massa quis 
enim. Donec pede justo, fringilla vel, aliquet nec, 
vulputate eget, arcu. In enim justo, rhoncus ut, 
imperdiet a, venenatis vitae, justo. Nullam dictum 
felis eu pede <a class="external ext" href="#">link</a> 
mollis pretium. Integer tincidunt. Cras dapibus. 
Vivamus elementum semper nisi. Aenean vulputate 
eleifend tellus. Aenean leo ligula, porttitor eu, 
consequat vitae, eleifend ac, enim. Aliquam lorem ante, 
dapibus in, viverra quis, feugiat a, tellus. Phasellus 
viverra nulla ut metus varius laoreet. Quisque rutrum. 
Aenean imperdiet. Etiam ultricies nisi vel augue. 
Curabitur ullamcorper ultricies nisi.</p>
<h1>Lorem ipsum dolor sit amet consectetuer adipiscing 
elit</h1>
<h2>Aenean commodo ligula eget dolor aenean massa</h2>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing 
elit. Aenean commodo ligula eget dolor. Aenean massa. 
Cum sociis natoque penatibus et magnis dis parturient 
montes, nascetur ridiculus mus. Donec quam felis, 
ultricies nec, pellentesque eu, pretium quis, sem.</p>
<h2>Aenean commodo ligula eget dolor aenean massa</h2>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing 
elit. Aenean commodo ligula eget dolor. Aenean massa. 
Cum sociis natoque penatibus et magnis dis parturient 
montes, nascetur ridiculus mus. Donec quam felis, 
ultricies nec, pellentesque eu, pretium quis, sem.</p>
<ul>
  <li>Lorem ipsum dolor sit amet consectetuer.</li>
  <li>Aenean commodo ligula eget dolor.</li>
  <li>Aenean massa cum sociis natoque penatibus.</li>
</ul>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing 
elit. Aenean commodo ligula eget dolor. Aenean massa. 
Cum sociis natoque penatibus et magnis dis parturient 
montes, nascetur ridiculus mus. Donec quam felis, 
ultricies nec, pellentesque eu, pretium quis, sem.</p>
<form action="#" method="post">
  <fieldset>
    <label for="name">Name:</label>
    <input type="text" id="name" placeholder="Enter your 
full name" />

    <label for="email">Email:</label>
    <input type="email" id="email" placeholder="Enter 
your email address" />

    <label for="message">Message:</label>
    <textarea id="message" placeholder="What's on your 
mind?"></textarea>

    <input type="submit" value="Send message" />

  </fieldset>
</form>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing 
elit. Aenean commodo ligula eget dolor. Aenean massa. 
Cum sociis natoque penatibus et magnis dis parturient 
montes, nascetur ridiculus mus. Donec quam felis, 
ultricies nec, pellentesque eu, pretium quis, sem.</p>
<table class="data">
  <tr>
    <th>Entry Header 1</th>
    <th>Entry Header 2</th>
    <th>Entry Header 3</th>
    <th>Entry Header 4</th>
  </tr>
  <tr>
    <td>Entry First Line 1</td>
    <td>Entry First Line 2</td>
    <td>Entry First Line 3</td>
    <td>Entry First Line 4</td>
  </tr>
  <tr>
    <td>Entry Line 1</td>
    <td>Entry Line 2</td>
    <td>Entry Line 3</td>
    <td>Entry Line 4</td>
  </tr>
  <tr>
    <td>Entry Last Line 1</td>
    <td>Entry Last Line 2</td>
    <td>Entry Last Line 3</td>
    <td>Entry Last Line 4</td>
  </tr>
</table>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing 
elit. Aenean commodo ligula eget dolor. Aenean massa. 
Cum sociis natoque penatibus et magnis dis parturient 
montes, nascetur ridiculus mus. Donec quam felis, 
ultricies nec, pellentesque eu, pretium quis, sem.</p>
  </div>

/*! normalize.css v3.0.2 | MIT License | git.io/normalize */

/**
 * 1. Set default font family to sans-serif.
 * 2. Prevent iOS text size adjust after orientation change, without disabling
 *    user zoom.
 */

html {
  font-family: sans-serif; /* 1 */
  -ms-text-size-adjust: 100%; /* 2 */
  -webkit-text-size-adjust: 100%; /* 2 */
}

/**
 * Remove default margin.
 */

body {
  margin: 0;
}

/* HTML5 display definitions
   ========================================================================== */

/**
 * Correct `block` display not defined for any HTML5 element in IE 8/9.
 * Correct `block` display not defined for `details` or `summary` in IE 10/11
 * and Firefox.
 * Correct `block` display not defined for `main` in IE 11.
 */

article,
aside,
details,
figcaption,
figure,
footer,
header,
hgroup,
main,
menu,
nav,
section,
summary {
  display: block;
}

/**
 * 1. Correct `inline-block` display not defined in IE 8/9.
 * 2. Normalize vertical alignment of `progress` in Chrome, Firefox, and Opera.
 */

audio,
canvas,
progress,
video {
  display: inline-block; /* 1 */
  vertical-align: baseline; /* 2 */
}

/**
 * Prevent modern browsers from displaying `audio` without controls.
 * Remove excess height in iOS 5 devices.
 */

audio:not([controls]) {
  display: none;
  height: 0;
}

/**
 * Address `[hidden]` styling not present in IE 8/9/10.
 * Hide the `template` element in IE 8/9/11, Safari, and Firefox < 22.
 */

[hidden],
template {
  display: none;
}

/* Links
   ========================================================================== */

/**
 * Remove the gray background color from active links in IE 10.
 */

a {
  background-color: transparent;
}

/**
 * Improve readability when focused and also mouse hovered in all browsers.
 */

a:active,
a:hover {
  outline: 0;
}

/* Text-level semantics
   ========================================================================== */

/**
 * Address styling not present in IE 8/9/10/11, Safari, and Chrome.
 */

abbr[title] {
  border-bottom: 1px dotted;
}

/**
 * Address style set to `bolder` in Firefox 4+, Safari, and Chrome.
 */

b,
strong {
  font-weight: bold;
}

/**
 * Address styling not present in Safari and Chrome.
 */

dfn {
  font-style: italic;
}

/**
 * Address variable `h1` font-size and margin within `section` and `article`
 * contexts in Firefox 4+, Safari, and Chrome.
 */

h1 {
  font-size: 2em;
  margin: 0.67em 0;
}

/**
 * Address styling not present in IE 8/9.
 */

mark {
  background: #ff0;
  color: #000;
}

/**
 * Address inconsistent and variable font size in all browsers.
 */

small {
  font-size: 80%;
}

/**
 * Prevent `sub` and `sup` affecting `line-height` in all browsers.
 */

sub,
sup {
  font-size: 75%;
  line-height: 0;
  position: relative;
  vertical-align: baseline;
}

sup {
  top: -0.5em;
}

sub {
  bottom: -0.25em;
}

/* Embedded content
   ========================================================================== */

/**
 * Remove border when inside `a` element in IE 8/9/10.
 */

img {
  border: 0;
}

/**
 * Correct overflow not hidden in IE 9/10/11.
 */

svg:not(:root) {
  overflow: hidden;
}

/* Grouping content
   ========================================================================== */

/**
 * Address margin not present in IE 8/9 and Safari.
 */

figure {
  margin: 1em 40px;
}

/**
 * Address differences between Firefox and other browsers.
 */

hr {
  -moz-box-sizing: content-box;
  box-sizing: content-box;
  height: 0;
}

/**
 * Contain overflow in all browsers.
 */

pre {
  overflow: auto;
}

/**
 * Address odd `em`-unit font size rendering in all browsers.
 */

code,
kbd,
pre,
samp {
  font-family: monospace, monospace;
  font-size: 1em;
}

/* Forms
   ========================================================================== */

/**
 * Known limitation: by default, Chrome and Safari on OS X allow very limited
 * styling of `select`, unless a `border` property is set.
 */

/**
 * 1. Correct color not being inherited.
 *    Known issue: affects color of disabled elements.
 * 2. Correct font properties not being inherited.
 * 3. Address margins set differently in Firefox 4+, Safari, and Chrome.
 */

button,
input,
optgroup,
select,
textarea {
  color: inherit; /* 1 */
  font: inherit; /* 2 */
  margin: 0; /* 3 */
}

/**
 * Address `overflow` set to `hidden` in IE 8/9/10/11.
 */

button {
  overflow: visible;
}

/**
 * Address inconsistent `text-transform` inheritance for `button` and `select`.
 * All other form control elements do not inherit `text-transform` values.
 * Correct `button` style inheritance in Firefox, IE 8/9/10/11, and Opera.
 * Correct `select` style inheritance in Firefox.
 */

button,
select {
  text-transform: none;
}

/**
 * 1. Avoid the WebKit bug in Android 4.0.* where (2) destroys native `audio`
 *    and `video` controls.
 * 2. Correct inability to style clickable `input` types in iOS.
 * 3. Improve usability and consistency of cursor style between image-type
 *    `input` and others.
 */

button,
html input[type="button"], /* 1 */
input[type="reset"],
input[type="submit"] {
  -webkit-appearance: button; /* 2 */
  cursor: pointer; /* 3 */
}

/**
 * Re-set default cursor for disabled elements.
 */

button[disabled],
html input[disabled] {
  cursor: default;
}

/**
 * Remove inner padding and border in Firefox 4+.
 */

button::-moz-focus-inner,
input::-moz-focus-inner {
  border: 0;
  padding: 0;
}

/**
 * Address Firefox 4+ setting `line-height` on `input` using `!important` in
 * the UA stylesheet.
 */

input {
  line-height: normal;
}

/**
 * It's recommended that you don't attempt to style these elements.
 * Firefox's implementation doesn't respect box-sizing, padding, or width.
 *
 * 1. Address box sizing set to `content-box` in IE 8/9/10.
 * 2. Remove excess padding in IE 8/9/10.
 */

input[type="checkbox"],
input[type="radio"] {
  box-sizing: border-box; /* 1 */
  padding: 0; /* 2 */
}

/**
 * Fix the cursor style for Chrome's increment/decrement buttons. For certain
 * `font-size` values of the `input`, it causes the cursor style of the
 * decrement button to change from `default` to `text`.
 */

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  height: auto;
}

/**
 * 1. Address `appearance` set to `searchfield` in Safari and Chrome.
 * 2. Address `box-sizing` set to `border-box` in Safari and Chrome
 *    (include `-moz` to future-proof).
 */

input[type="search"] {
  -webkit-appearance: textfield; /* 1 */
  -moz-box-sizing: content-box;
  -webkit-box-sizing: content-box; /* 2 */
  box-sizing: content-box;
}

/**
 * Remove inner padding and search cancel button in Safari and Chrome on OS X.
 * Safari (but not Chrome) clips the cancel button when the search input has
 * padding (and `textfield` appearance).
 */

input[type="search"]::-webkit-search-cancel-button,
input[type="search"]::-webkit-search-decoration {
  -webkit-appearance: none;
}

/**
 * Define consistent border, margin, and padding.
 */

fieldset {
  border: 1px solid #c0c0c0;
  margin: 0 2px;
  padding: 0.35em 0.625em 0.75em;
}

/**
 * 1. Correct `color` not being inherited in IE 8/9/10/11.
 * 2. Remove padding so people aren't caught out if they zero out fieldsets.
 */

legend {
  border: 0; /* 1 */
  padding: 0; /* 2 */
}

/**
 * Remove default vertical scrollbar in IE 8/9/10/11.
 */

textarea {
  overflow: auto;
}

/**
 * Don't inherit the `font-weight` (applied by a rule above).
 * NOTE: the default cannot safely be changed in Chrome and Safari on OS X.
 */

optgroup {
  font-weight: bold;
}

/* Tables
   ========================================================================== */

/**
 * Remove most spacing between table cells.
 */

table {
  border-collapse: collapse;
  border-spacing: 0;
}

td,
th {
  padding: 0;
}

function drop(css, html) {
  return dropcss({
    css,
    html,
  });
}

let oldCss = null;
let pre = document.createElement("pre");
pre.style.whiteSpace = 'pre-wrap';
pre.style.fontSize = '10pt';
pre.style.position = 'fixed';
pre.style.left = "calc(50% - 300px)";
pre.style.top = "calc(50% - 150px)";
pre.style.padding = "10px";
pre.style.background = "#f0f0f0";
pre.style.border = "1px solid gray";
pre.style.minWidth = "300px";
pre.style.maxWidth = "33.3333%";
pre.style.overflow = "scroll";
pre.style.height = "50vh";
document.body.appendChild(pre);
render();
setInterval(render, 250);

function render() {
  let css = document.querySelector("style").textContent;
  if (css != oldCss) {
    let html = document.querySelector("#root").outerHTML;
    let start = +new Date();
    let cleaned = drop(css, html);
    let elapsed = +new Date() - start;
    pre.textContent = [
      "未使用のCSSを削除しました (" + elapsed + "秒かかりました)\n",
      "==================\n",
      cleaned.css,
    ].join("\n");
    oldCss = css;
  }
}