<details>
  <summary>Look Ma. <strong>No JavaScript</strong>. 🤓</summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placebear.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>
<details>
  <summary>These work with just <strong>CSS</strong> and <strong>Semantic HTML</strong> 👍</summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placebear.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>
<details>
  <summary>Click or Tap <strong>ANYWHERE</strong> to expand with a <strong>Sliding Effect</strong></summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placebear.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>

<details class="style2">
  <summary>Another <strong>STYLE</strong> of indicator.</summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placebear.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>

<details class="style3">
  <summary>Yet another <strong>STYLE</strong> of indicator.</summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placebear.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>

<details class="style4">
  <summary>Yet another <strong>STYLE</strong> of indicator.</summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placebear.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>

<details class="style5">
  <summary><span class="monkey-see">What does monkey <strong>KNOW</strong>?</span><span class="monkey-hide"><strong>SHHHHHHHHH</strong> be quite monkey!</span></summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placemonkeys.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>

<details class="style6">
  <summary>Yet another <strong>STYLE</strong> of indicator.</summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://placebear.com/400/200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>

<details class="style7">
  <summary><span class="moon-new">Want to learn about the <strong>MOON</strong>?</span><span class="moon-full">The <strong>MOON</strong> is <strong>AMAZING</strong>!</span></summary>
  <div class="content">
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Modi unde, ex rem voluptates autem aliquid veniam quis temporibus repudiandae illo, nostrum, pariatur quae! At animi modi dignissimos corrupti placeat voluptatum!
    </p>
    <img src="https://spaceholder.cc/400x200" alt="">
    <p>
      Facilis ducimus iure officia quos possimus quaerat iusto, quas, laboriosam sapiente autem ab assumenda eligendi voluptatum nisi eius cumque, tempore reprehenderit optio placeat praesentium non sint repellendus consequuntur? Nihil, soluta.
    </p>
  </div>
</details>

/* # The Rotating Marker # */
details summary::-webkit-details-marker { display: none; }
summary::before {
  font-family: "Hiragino Mincho ProN", "Open Sans", sans-serif;
  content: "▶";
  position: absolute;
  top: 1rem;
  left: 0.8rem;
  transform: rotate(0);
  transform-origin: center;
  transition: 0.2s transform ease;
}
details[open] > summary:before {
  transform: rotate(90deg);
  transition: 0.45s transform ease;
}

/* # The Sliding Summary # */
details { overflow: hidden; }
details summary {
  position: relative;
  z-index: 10;
}
@keyframes details-show {
  from {
    margin-bottom: -80%;
    opacity: 0;
    transform: translateY(-100%);
  }
}
details > *:not(summary) {
  animation: details-show 500ms ease-in-out;
  position: relative;
  z-index: 1;
  transition: all 0.3s ease-in-out;
  color: transparent;
  overflow: hidden;
}
details[open] > *:not(summary) { color: inherit; }

/* # Style 2 # */
details.style2 summary::before {
  content: "×";
  color: #FFF;
  font-size: 2rem;
  line-height: 1rem;
  transform: rotate(-45deg);
  top: 1.2rem;
  left: 0.5rem;
}
details[open].style2 > summary:before {
  transform: rotate(90deg);
  color: #F00 !important;
  transition: color ease 2s, transform ease 1s;
}

/* # Style 3 # */
details.style3 summary::before {
  content: "›";
  font-size: 2.5rem;
  line-height: 1rem;
  top: 1.3rem;
  left: 0rem;
  margin: -0.5rem -0.5rem 0 0.5rem;
  transform-origin: bottom center;
  transition: margin linear 0.05s;
}
details.style3:hover > summary:before {
  color: #FFF;
}
details[open].style3 > summary:before {
  left: 0rem;
  color: #CCC;
  transform: rotate(90deg);
  margin-left: 0.4rem;
  transition: color ease 2s, transform ease 1s, margin ease 1s;
}
@supports (-webkit-touch-callout: none) {
  details.style3 summary::before { top: 1.6rem; }
  details[open].style3 > summary:before { top: 1.3rem; transition: all 0.8s; }
}

/* # Style 4 # */
details.style4 summary {
  padding-right: 2.2rem;
  padding-left: 1rem;
}
details.style4 summary::before {
  content: "×";
  color: #FFF;
  font-size: 2rem;
  line-height: 1rem;
  transform: rotate(-45deg);
  top: 1.2rem;
  left: unset;
  right: 0.6rem;
}
details[open].style4 > summary:before {
  transform: rotate(90deg);
  color: #F00 !important;
  transition: color ease 2s, transform ease 1s;
}

/* # Style 5 # */
details.style5 summary {
  padding-right: 2.2rem;
  padding-left: 1rem;
}
details.style5 summary::before {
  content: "🙈";
  font-size: 1.5rem;
  top: 0.5rem;
  left: unset;
  right: 0.5rem;
  transform: rotate(0);
}
details.style5:hover > summary::before {
  content: "🙊";
}
details[open].style5 > summary::before {
  content: "🐵";
  transform: rotate(0deg);
}
details[open].style5 > summary:hover::before {
  content: "🙉";
}
details .monkey-see { display: inline; }
details .monkey-hide { display: none; }
details[open] .monkey-see { display: none; }
details[open] .monkey-hide { display: inline; }

/* # Style 6 # */
details.style6 summary {
  padding-right: 2.2rem;
  padding-left: 1rem;
}
details.style6 summary::before {
  content: "❔";
  font-size: 1.5rem;
  top: 0.5rem;
  left: unset;
  right: 0.5rem;
  transform: rotate(0);
}
details.style6:hover > summary:before {
  content: "👁️‍🗨️";
}
details[open].style6 > summary:before {
  content: "❌";
  transform: rotate(0deg);
}

/* # Style 7 # */
details.style7 summary {
  padding-left: 3rem;
}
details[open].style7 summary,
details.style7:hover summary {
  background: #000;
  color: #CCC;
}
details[open].style7 summary strong,
details.style7:hover summary strong {
  color: #FDCE4C;
}
details.style7:hover summary strong { color: #ffdf87; }
details.style7 summary::before {
  content: "🌑";
  font-size: 1.5rem;
  top: 0.5rem;
  left: 0.5rem;
  transform: rotate(0);
}
details.style7:hover > summary::before {
  content: "🌕";
}
details[open].style7 > summary::before {
  content: "🌕";
  transform: rotate(0deg);
}
details[open].style7 > summary:hover::before {
  content: "🌕";
}
details .moon-new { display: inline; }
details .moon-full { display: none; }
details[open] .moon-new { display: none; }
details[open] .moon-full { display: inline; }
details.style7 .content { background: #DDD; }

/* # Just Some Pretty Styles # */
body { font-family: "Open Sans", sans-serif; padding-bottom: 400px; }
img { max-width: 100%; }
p { margin: 0; padding-bottom: 10px; }
p:last-child { padding: 0; }
details {
  max-width: 500px;
  box-sizing: border-box;
  margin-top: 5px;
  background: white;
}
summary {
  border: 4px solid transparent;
  outline: none;
  padding: 1rem;
  display: block;
  background: #666;
  color: white;
  padding-left: 2.2rem;
  position: relative;
  cursor: pointer;
}
details[open] summary,
summary:hover {
  color: #FFCA28;
  background: #444;
}
summary:hover strong,
details[open] summary strong,
summary:hover::before,
details[open] summary::before {
  color: #FFA128;
}
.content {
  padding: 10px;
  border: 2px solid #888;
  border-top: none;
}