CSS solution to make drop-down element visible while focused - css

Question

I'm trying to figure out if there is any pure CSS solution to keep a drop-down element open while the input field of that element is focused? Here is an example:
div {
width: 300px;
line-height: 50px;
text-align: center;
background: #e8e8e8;
border: 1px solid #666;
}
div:hover form {
display: block;
}
form {
display: none;
padding: 0 15px;
}
<div>Hover Me
<form class="search">
<input type="search" placeholder="What are you looking for?" autofocus>
<input type="button" value="Search!">
</form>
</div>
The idea is to keep the form visible when the search field is focused. Because when a user starts typing the search inquiry and the mouse move out of the hover zone, the form hides, and that's very annoying.
Side-question: Is it possible to focus via CSS search input element each time a <div> is hovered?

Answer 1

The solution has been already proposed, but lacks browser support:
9.4. The Generalized Input Focus Pseudo-class: :focus-within
The :focus-within pseudo-class applies to elements for which the
:focus pseudo class applies.
An element also matches :focus-within if one of its
shadow-including descendants matches :focus.
div {
width: 300px;
line-height: 50px;
text-align: center;
background: #e8e8e8;
border: 1px solid #666;
}
div:hover form, div:focus-within form {
display: block;
}
form {
display: none;
padding: 0 15px;
}
<div tabindex="-1">Hover Me
<form class="search">
<input type="search" placeholder="What are you looking for?" autofocus>
<input type="button" value="Search!">
</form>
</div>
Meanwhile, you can use a polyfill:
div {
width: 300px;
line-height: 50px;
text-align: center;
background: #e8e8e8;
border: 1px solid #666;
}
div:hover form, div.focus-within form {
display: block;
}
form {
display: none;
padding: 0 15px;
}
<script src="https://gist.githubusercontent.com/aFarkas/a7e0d85450f323d5e164/raw/"></script>
<div tabindex="-1">Hover Me
<form class="search">
<input type="search" placeholder="What are you looking for?" autofocus>
<input type="button" value="Search!">
</form>
</div>

Answer 2

Wait. There's actually a pure CSS solution. But there is a drawback — it only works with just one <input> tag, and no <form> tag, like this:
div {
width: 300px;
line-height: 50px;
text-align: center;
background: #e8e8e8;
border: 1px solid #666;
padding: 0.5%;
}
input {
display: none;
margin: auto;
}
div:hover input {
display: block;
}
input:focus {
display: block !important
}
<div>Hover Me
<input type="search" placeholder="What are you looking for?">
</form>
</div>
However, you can just make the user search the form by pressing Enter on the keyboard. Unfortunately, this requires JavaScript, which defeats the whole purpose of this post.
I've also noticed that your placeholder text doesn't really work properly, since the text "Search" is still there. There are two solutions to this — use JavaScript to fix it, or change the 'type' of the input tag to "text".