Collapsible text height in pure css

Question

Here's a snippet of what I have so far:

#expand {
  height: 0px;
  width: 0px;
  overflow: hidden;
  transition: height 0.5s, width 0.5s ease-in-out;
  background: #000000;
  color: #FFF;
}

input {
  display: none;
  visibility: hidden;
}

input:checked+label+#expand {
  height: 150px;
  width: 600px;
}

#toggle:checked~label::before {
  content: "-";
}


/* useless styling */

main {
  background: #EEE;
  width: 100px;
  margin: 20px auto;
  padding: 10px 0;
  box-shadow: 0 3px 5px rgba(0, 0, 0, 0.3);
}

section {
  padding: 0 20px;
}

label {
  display: block;
  padding: 0.5em;
  text-align: center;
  border-bottom: 1px solid #CCC;
  color: #666;
}

label:hover {
  color: #000;
}

label::before {
  font-family: Consolas, monaco, monospace;
  font-weight: bold;
  font-size: 15px;
  content: "+";
  vertical-align: text-top;
  display: inline-block;
  width: 20px;
  height: 20px;
  margin-right: 3px;
  background: radial-gradient(ellipse at center, #CCC 50%, transparent 50%);
}

<main>
  <input id="toggle" type="checkbox" />
  <label for="toggle">Hidden Kitten</label>
  <div id="expand">
    <section>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.
        It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with
        desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
    </section>
  </div>

  <input id="toggle1" type="checkbox" />
  <label for="toggle1">Hidden Kitten</label>
  <div id="expand">
    <section>
      <p>mew</p>
    </section>
  </div>
</main>

You can see in the input:checked + label + #expand selector, the width and height are fixed.

I can set the width to a percentage just fine, but if I try to set the height to a percentage it ruins the animation. How do I fix this? I do not know the text's height beforehand. I would like to use only CSS for this.

@cale_b that answer was exactly what i needed, thanks! i'll still mark Quantastical's answer as correct since he posted it first. — Zee, May 30 '19 at 16:25

score 1 · Accepted Answer · edited May 30 '19 at 16:39

You can try using max-height instead of height.

#expand {
  max-height: 0px;
  width: 0px;
  overflow: hidden;
  transition: max-height 0.5s, width 0.5s ease-in-out;
  background: #000000;
  color: #FFF;
}

input {
  display: none;
  visibility: hidden;
}

input:checked+label+#expand {
  max-height: 150px;
  width: 600px;
}

#toggle:checked~label::before {
  content: "-";
}


/* useless styling */

main {
  background: #EEE;
  width: 100px;
  margin: 20px auto;
  padding: 10px 0;
  box-shadow: 0 3px 5px rgba(0, 0, 0, 0.3);
}

section {
  padding: 0 20px;
}

label {
  display: block;
  padding: 0.5em;
  text-align: center;
  border-bottom: 1px solid #CCC;
  color: #666;
}

label:hover {
  color: #000;
}

label::before {
  font-family: Consolas, monaco, monospace;
  font-weight: bold;
  font-size: 15px;
  content: "+";
  vertical-align: text-top;
  display: inline-block;
  width: 20px;
  height: 20px;
  margin-right: 3px;
  background: radial-gradient(ellipse at center, #CCC 50%, transparent 50%);
}

<main>
  <input id="toggle" type="checkbox" />
  <label for="toggle">Hidden Kitten</label>
  <div id="expand">
    <section>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.
        It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with
        desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
    </section>
  </div>

  <input id="toggle1" type="checkbox" />
  <label for="toggle1">Hidden Kitten</label>
  <div id="expand">
    <section>
      <p>mew</p>
    </section>
  </div>
</main>

Collapsible text height in pure css

1 Answers1