CSS: Change parent on focus of child

Question

Let's say you have something like:

<div class="parent">
    <input class="childInput" type="text" />
    <div class="sibling"></div>
</div>

I want to change the appearance of the parent/siblings when the child receives focus. Are there any CSS tricks for doing stuff like this?

Edit:

The reason for my question is as follows:

I'm creating an Angular app which needs editable text fields. It should look like a label until it is clicked, at which point it should look like a normal text input. I styled the text field based on :focus to achieve this effect, but the text is cut off by text input's boundaries. I also used ng-show, ng-hide, ng-blur, ng-keypress and ng-click to switch between the label and the text input based on blurs, key presses and clicks. This worked fine except for one thing: After the label's ng-click="setEdit(this, $event)" changes the edit boolean used by ng-show and ng-hide to true, it uses a jQuery call to .select() the text input. However, it isn't until after the completion of the ng-click that everything is $digest'd, so the text input loses focus again. Since the text input never actually receives focus, using ng-blur to revert back to showing the label is buggy: The user has to click in the text input and then click out of it again to revert back to showing the label.

Edit:

Here's an example plunk of the issue: http://plnkr.co/edit/synSIP?p=preview

Answer 1

You can now do this in pure CSS, so no JavaScript needed 😁

The new CSS pseudo-class :focus-within would help for cases like this and will help with accessibility when people use tabbing for navigating, common when using screen readers.

.parent:focus-within {
  border: 1px solid #000;
}

The :focus-within pseudo-class matches elements that either themselves match :focus or that have descendants which match :focus.

---

Can I use...

You can check which browsers support this by visiting http://caniuse.com/#search=focus-within

---

Demo

fieldset {
  padding: 0 24px 24px !important;
}

fieldset legend {
  opacity: 0;
  padding: 0 8px;
  width: auto;
}

fieldset:focus-within {
  border: 1px solid #000;
}

fieldset:focus-within legend {
  opacity: 1;
}

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" />

<div class="container">
  <form>
    <fieldset>
      <legend>Parent Element</legend>
      <div class="form-group">
        <label for="name">Name:</label>
        <input class="form-control" id="name" placeholder="Enter name">
      </div>
      <div class="form-group">
        <label for="email">Email:</label>
        <input type="email" class="form-control" id="email" placeholder="Enter email">
      </div>
    </fieldset>
  </form>
</div>