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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              <main>
  <article>
    <h1>Dark mode should be a user preference—not presumed</h1>
    <p>Yes, by default, when a user has <code>@media (prefers-color-scheme: dark)</code> set, we should set a dark theme, but we should also provide a switch for if the dark them isn’t working out for them.</p>
    <p>This also benefits users that don’t have <code>@media (prefers-color-scheme: dark)</code> set because they get a toggle to choose, too.</p>
  </article>
  <div class="user-toggle">
    <div role="status" class="[ visually-hidden ][ js-mode-status ]"></div>
    <button class="[ toggle-button ] [ js-mode-toggle ]">
      <span class="[ toggle-button__text ] [ js-mode-toggle-text ]">Enable dark mode</span>
      <span class="toggle-button__icon" aria-hidden="true"></span>
    </button>
  </div>
</main>
            
          
!
            
              :root {
  --color-mode: 'light';
  --color-dark: #141414;
  --color-dark-alpha: rgba(0, 0, 0, 0.1);
  --color-light: #efefef;
  --color-light-alpha: rgba(255, 255, 255, 0.9);
  
  /* https://twitter.com/Una/status/1129401554732277760 */
  --icon-sun: url('data:image/svg+xml,\
  <svg version="1.1" xmlns="http://www.w3.org/2000/svg" fill="currentColor" viewBox="0 0 24 24">\
    <path d="M18 12c0-0.811-0.161-1.587-0.455-2.295-0.304-0.735-0.75-1.395-1.303-1.948-0.552-0.552-1.213-0.998-1.948-1.303-0.707-0.293-1.483-0.454-2.294-0.454s-1.587 0.161-2.295 0.455c-0.735 0.304-1.395 0.75-1.948 1.302s-0.998 1.213-1.302 1.948c-0.294 0.708-0.455 1.484-0.455 2.295s0.161 1.587 0.455 2.295c0.304 0.735 0.75 1.395 1.303 1.948 0.552 0.552 1.213 0.998 1.948 1.303 0.707 0.293 1.483 0.454 2.294 0.454s1.587-0.161 2.295-0.455c0.735-0.304 1.395-0.75 1.948-1.303s0.998-1.213 1.303-1.948c0.293-0.707 0.454-1.483 0.454-2.294zM16 12c0 0.544-0.108 1.060-0.303 1.529-0.202 0.489-0.5 0.929-0.869 1.299s-0.81 0.667-1.299 0.869c-0.469 0.195-0.985 0.303-1.529 0.303s-1.060-0.108-1.529-0.303c-0.489-0.202-0.929-0.5-1.299-0.869s-0.667-0.81-0.869-1.299c-0.195-0.469-0.303-0.985-0.303-1.529s0.108-1.060 0.303-1.529c0.202-0.489 0.5-0.929 0.869-1.299s0.81-0.667 1.299-0.869c0.469-0.195 0.985-0.303 1.529-0.303s1.060 0.108 1.529 0.303c0.489 0.202 0.929 0.5 1.299 0.869s0.667 0.81 0.869 1.299c0.195 0.469 0.303 0.985 0.303 1.529zM11 1v2c0 0.552 0.448 1 1 1s1-0.448 1-1v-2c0-0.552-0.448-1-1-1s-1 0.448-1 1zM11 21v2c0 0.552 0.448 1 1 1s1-0.448 1-1v-2c0-0.552-0.448-1-1-1s-1 0.448-1 1zM3.513 4.927l1.42 1.42c0.391 0.391 1.024 0.391 1.414 0s0.391-1.024 0-1.414l-1.42-1.42c-0.391-0.391-1.024-0.391-1.414 0s-0.391 1.024 0 1.414zM17.653 19.067l1.42 1.42c0.391 0.391 1.024 0.391 1.414 0s0.391-1.024 0-1.414l-1.42-1.42c-0.391-0.391-1.024-0.391-1.414 0s-0.391 1.024 0 1.414zM1 13h2c0.552 0 1-0.448 1-1s-0.448-1-1-1h-2c-0.552 0-1 0.448-1 1s0.448 1 1 1zM21 13h2c0.552 0 1-0.448 1-1s-0.448-1-1-1h-2c-0.552 0-1 0.448-1 1s0.448 1 1 1zM4.927 20.487l1.42-1.42c0.391-0.391 0.391-1.024 0-1.414s-1.024-0.391-1.414 0l-1.42 1.42c-0.391 0.391-0.391 1.024 0 1.414s1.024 0.391 1.414 0zM19.067 6.347l1.42-1.42c0.391-0.391 0.391-1.024 0-1.414s-1.024-0.391-1.414 0l-1.42 1.42c-0.391 0.391-0.391 1.024 0 1.414s1.024 0.391 1.414 0z"></path>\
  </svg>');
  
  /* https://css-tricks.com/the-many-ways-to-change-an-svg-fill-on-hover-and-when-to-use-them/ */
  --icon-sun-filter: invert(0.61) sepia(0.8) saturate(5) hue-rotate(0deg) brightness(0.92);
  
  --icon-moon: url('data:image/svg+xml,\
  <svg version="1.1" xmlns="http://www.w3.org/2000/svg" fill="currentColor" viewBox="0 0 24 24">\
    <path d="M21.996 12.882c0.022-0.233-0.038-0.476-0.188-0.681-0.325-0.446-0.951-0.544-1.397-0.219-0.95 0.693-2.059 1.086-3.188 1.162-0.696 0.047-1.399-0.027-2.077-0.226-0.656-0.192-1.29-0.501-1.874-0.932-0.655-0.484-1.181-1.074-1.575-1.729-0.409-0.68-0.676-1.432-0.792-2.206s-0.082-1.571 0.11-2.342c0.184-0.741 0.514-1.46 0.999-2.115 0.142-0.191 0.216-0.435 0.191-0.691-0.053-0.55-0.542-0.952-1.092-0.898-1.117 0.109-2.186 0.399-3.172 0.843-1.005 0.452-1.925 1.065-2.723 1.808-0.883 0.82-1.618 1.801-2.159 2.901-0.523 1.064-0.863 2.238-0.978 3.485-0.125 1.347 0.024 2.658 0.402 3.878 0.392 1.266 1.031 2.431 1.863 3.433s1.86 1.843 3.033 2.461c1.13 0.595 2.392 0.982 3.739 1.106s2.659-0.025 3.878-0.403c1.266-0.392 2.431-1.031 3.433-1.863s1.843-1.86 2.461-3.033c0.595-1.13 0.982-2.392 1.106-3.739zM19.567 14.674c-0.126 0.351-0.276 0.689-0.447 1.014-0.493 0.937-1.166 1.76-1.969 2.427s-1.735 1.178-2.747 1.491c-0.973 0.302-2.021 0.421-3.102 0.321s-2.089-0.41-2.99-0.884c-0.937-0.493-1.76-1.166-2.427-1.969s-1.178-1.735-1.491-2.747c-0.302-0.973-0.421-2.021-0.321-3.102 0.092-1 0.365-1.938 0.782-2.786 0.43-0.878 1.018-1.661 1.725-2.319 0.64-0.595 1.377-1.086 2.183-1.449 0.179-0.081 0.362-0.155 0.548-0.223-0.092 0.257-0.171 0.516-0.236 0.778-0.256 1.029-0.302 2.091-0.147 3.121s0.51 2.032 1.056 2.941c0.527 0.875 1.23 1.663 2.1 2.306 0.775 0.573 1.622 0.986 2.5 1.243 0.907 0.266 1.846 0.364 2.772 0.302 0.752-0.050 1.496-0.207 2.21-0.465z"></path>\
  </svg>');
  --icon-moon-filter: invert(0.75);
  
  --background: #efefef;
  --text-color: #141414;
  --button-icon: var(--icon-moon);
  --button-icon-filter: var(--icon-moon-filter);
  --button-background: var(--color-dark);
  --button-color: var(--color-light);
  --border-color: var(--color-dark-alpha);
}

body {
  background: var(--background);
  color: var(--text-color);
  transition: background 500ms ease-in-out, color 200ms ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-mode: 'dark';
  }
  
  :root:not([data-user-color-scheme]) {
    --background: var(--color-dark);
    --text-color: var(--color-light);
    --button-icon: var(--icon-sun);
    --button-icon-filter: var(--icon-sun-filter);
    --button-background: var(--color-light);
    --button-color: var(--color-dark);
    --border-color: var(--color-light-alpha);
  }
}

[data-user-color-scheme="dark"] {
  --background: var(--color-dark);
  --text-color: var(--color-light);
  --button-icon: var(--icon-sun);
  --button-icon-filter: var(--icon-sun-filter);
  --button-background: var(--color-light-alpha);
  --button-color: var(--color-dark);
  --border-color: var(--color-light-alpha);
}

/* Remove _all_ animations and transitions for people that prefer not to see them */
@media (prefers-reduced-motion: reduce) {
  body {
    scroll-behavior: auto;
  }

  * {
    -webkit-animation: none !important;
    animation: none !important;
    transition: none !important;
  }
}

/* If there’s no JS, there’s no need for the user toggle component to show */
.no-js .user-toggle {
  display: none;
}

.user-toggle {
  margin: 2rem auto 0 auto;
  padding-top: 2.5rem;
  max-width: 20rem;
  border-top: 1px solid var(--border-color);
  text-align: center;
}

.toggle-button {
  display: inline-flex;
  background: var(--button-background);
  color: var(--button-color);
  border: none;
  font: inherit;
  font-size: 1.5rem;
  padding: 0.5rem 1rem;
  transition: background 500ms ease-in-out, color 200ms ease;
}

.toggle-button__icon {
  background: var(--button-icon);
  width: 1.2em; 
  height: 1.2em;
  margin: 0 0 0 0.5em;
  filter: var(--button-icon-filter);
  transform: translateY(1px); /* Optical adjustment */
  transition: filter 500ms ease-in-out;
}

.toggle-button:focus {
  outline: 1px solid var(--button-background);
  outline-offset: 0.5rem;
}










/* Presentational demo styles */

body {
  font-family: sans-serif;
  padding: 2rem 1rem;
  line-height: 1.4;
  display: grid;
  place-items: center;
}

article {
  max-width: 75ch;
  margin: 0 auto;
}

article > * + * {
  margin-top: 1em;
}

h1 {
  font-size: 2.5rem;
  line-height: 1.1;
}

p {
  font-size: 1.2rem;
  opacity: 0.9;
}

code {
  font-weight: 700;
  font-size: 1.3em;
  white-space: pre;
}

.visually-hidden { 
  display: block;
  height: 1px;
  width: 1px;
  overflow: hidden;
  clip: rect(1px 1px 1px 1px);
  clip: rect(1px, 1px, 1px, 1px);
  clip-path: inset(1px);
  white-space: nowrap;
  position: absolute;
}
            
          
!
            
              // Remove the no JS class so that the button will show
document.documentElement.classList.remove('no-js');

const STORAGE_KEY = 'user-color-scheme';
const COLOR_MODE_KEY = '--color-mode';

const modeToggleButton = document.querySelector('.js-mode-toggle');
const modeToggleText = document.querySelector('.js-mode-toggle-text');
const modeStatusElement = document.querySelector('.js-mode-status');

/**
 * Pass in a custom prop key and this function will return its
 * computed value. 
 * A reduced version of this: https://andy-bell.design/wrote/get-css-custom-property-value-with-javascript/
 */
const getCSSCustomProp = (propKey) => {
  let response = getComputedStyle(document.documentElement).getPropertyValue(propKey);

  // Tidy up the string if there’s something to work with
  if (response.length) {
    response = response.replace(/\'|"/g, '').trim();
  }

  // Return the string response by default
  return response;
};

/**
 * Takes either a passed settings ('light'|'dark') or grabs that from localStorage.
 * If it can’t find the setting in either, it tries to load the CSS color mode,
 * controlled by the media query
 */
const applySetting = passedSetting => {
  let currentSetting = passedSetting || localStorage.getItem(STORAGE_KEY);
  
  if(currentSetting) {
    document.documentElement.setAttribute('data-user-color-scheme', currentSetting);
    setButtonLabelAndStatus(currentSetting);
  }
  else {
    setButtonLabelAndStatus(getCSSCustomProp(COLOR_MODE_KEY));
  }
}

/**
 * Get’s the current setting > reverses it > stores it
 */
const toggleSetting = () => {
  let currentSetting = localStorage.getItem(STORAGE_KEY);
  
  switch(currentSetting) {
    case null:
      currentSetting = getCSSCustomProp(COLOR_MODE_KEY) === 'dark' ? 'light' : 'dark';
      break;
    case 'light':
      currentSetting = 'dark';
      break;
    case 'dark':
      currentSetting = 'light';
      break;
  }


  localStorage.setItem(STORAGE_KEY, currentSetting);
  
  return currentSetting;
}

/**
 * A shared method for setting the button text label and visually hidden status element 
 */
const setButtonLabelAndStatus = currentSetting => { 
  modeToggleText.innerText = `Enable ${currentSetting === 'dark' ? 'light' : 'dark'} mode`;
  modeStatusElement.innerText = `Color mode is now "${currentSetting}"`;
}

/**
 * Clicking the button runs the apply setting method which grabs its parameter
 * from the toggle setting method.
 */
modeToggleButton.addEventListener('click', evt => {
  evt.preventDefault();
  
  applySetting(toggleSetting());
});

applySetting();
            
          
!
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