How can I set the height of an outer div to always be equal to the height of a specific inner div?

Question

I have an outer div that contains three inner divs.

I want the leftmost inner div to always determine the height of the outer div. If the other inner divs have less content [than the leftmost div], they will have empty space. If they have more content [than the leftmost div], they will get a scrollbar.

Some other questions on SO ask how to set the height of an outer div to the height of an inner div. However, in my case, I have multiple inner divs, and I don't know if the height of the outer div is greater or less than the height of the leftmost div.

Is there any way to do this, specifically using only CSS?

Answer 1

different way. Two examples:

.outer_div {
  position: relative;
  overflow: hidden;
  max-width: 300px;
  margin: 0 auto;
}
.inner_div {
  width: 33.33%;
}
.inner_div_1 {
  float: left;
  background: khaki;
}
.inner_div_2,
.inner_div_3 {
  background: darkkhaki;
  position: absolute;
  top: 0;
  height: 100%;
  overflow-y: auto;
}
.inner_div_2 {
  left: 33.33%;
}
.inner_div_3 {
  left: 66.66%;
}

<div class="outer_div">
  <div class="inner_div inner_div_1">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
  </div>
  <div class="inner_div inner_div_2">
    Lorem ipsum.
  </div>
  <div class="inner_div inner_div_3">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </div>
</div>

.outer_div {
  display: flex;
  flex-direction: row;
  max-width: 300px;
  margin: 0 auto;
  background : gray;
}
.inner_div {
  width: 33.33%;
}
.inner_div > div {
  position: relative;
  height: 100%;
}
.inner_div_1 span {
  background: khaki;
}
.inner_div_2 span,
.inner_div_3 span {
  background: darkkhaki;
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
}

<div class="outer_div">
  <div class="inner_div inner_div_1">
    <span>
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
    </span>
  </div>
  <div class="inner_div inner_div_2">
    <div>
      <span>
        Lorem ipsum.
      </span>
    </div>
  </div>
  <div class="inner_div inner_div_3">
    <div>
      <span>
        Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
      </span>
    </div>
  </div>
</div>

Answer 2

One idea is to use absolute positioning to separate some content from the flow so it doesn't have any effect on the height, and then use Flexbox as the main layout:

.container {
  display: flex;
  border: 1px solid;
  padding: 5px;
  box-sizing: border-box;
}

.container>div {
  flex: 1;
  margin: 5px;
  border: 1px solid;
  box-sizing: border-box;
}
div.inner {
  border-color:red;
}

.inner-alt {
  position: relative;
  overflow: auto;
}

.inner-alt>div {
  position: absolute;
  top: 0;
  right: 0;
  left: 0;
  bottom: 0;
}

<div class="container">
  <div class="inner">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec dignissim ipsum orci, </div>
  <div class="inner-alt">
    <div>ut volutpat ligula finibus a. Maecenas ut pharetra ante. Nunc volutpat est eu odio vestibulum, eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate. Vivamus ac tincidu</div>
  </div>
  <div class="inner-alt">
    <div>eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate. Vivamus ac tincidu</div>
  </div>
</div>
<div class="container">
  <div class="inner">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec dignissim ipsum orci, io vestibulum, eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate</div>
  <div class="inner-alt">
    <div>ut volutpat ligula finibus a. Maecenas ut pharetra ante. Nunc volutpat est eu odio vestibulum, eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate. Vivamus ac tincidu</div>
  </div>
  <div class="inner-alt">
    <div>eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate. Vivamus ac tincidu</div>
  </div>
</div>
<div class="container">
  <div class="inner">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec dignissim ipsum orci, io vestibulum, eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate , eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate</div>
  <div class="inner-alt">
    <div>ut volutpat ligula finibus a. Maecenas ut pharetra ante. Nunc volutpat est eu odio vestibulum, eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate. Vivamus ac tincidu</div>
  </div>
  <div class="inner-alt">
    <div>eget bibendum risus commodo. Nullam tristique nibh sed iaculis vulputate. Vivamus ac tincidu</div>
  </div>
</div>