Input box is not full width

I cannot understand why my input box does not take full width.

I use tailwind css.

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-html -->

<div class="flex flex-col md:flex-row md:items-center md:justify-between">
  <div class="flex flex-row items-center">
    <div class="icon">ICON</div>
    <div class="brand">BRAND</div>
  </div>
  <div class="flex grow">
    <span class="relative flex w-full items-center bg-green-200 p-4">
      <label for="search"></label>
      <div class="icon absolute">ICON</div>
      <input placeholder="WHY NOT FULL WIDTH FOR THIS INPUT BOX?????" class=""
    /></span>
  </div>
  <div class="flex flex-row">SECTION-2</div>
</div>

<!-- end snippet -->

If I replace the input element with a div for example then it is all correct, that div takes full width. But for some reason the input element does not. Why?

Photo from Solution (original --> successfully)

Link to Example

More information: How to use "grow" in item of "flex"

Code

<!-- Flex Container -->
<div class="flex flex-col md:flex-row md:items-center md:justify-between">
    <!-- Flex Item List -->
  
    <!-- 1. -->
    <div class="icon">ICON</div>
  
    <!-- 2. -->
    <div class="brand">BRAND</div>
  
    <!-- 3. - fill empty places by "grow" -->
    <!-- Need one-line so we added flex class -> (Sub) Flex Container -->
    <span class="grow bg-green-200 p-4 flex">
        <!-- (Sub) Flex Item List -->

        <!-- 1. -->
        <label for="search"></label>

        <!-- 2. -->
        <div class="icon">ICON</div>

        <!-- 3. -->
        <!-- fill empty places by "grow" -->
        <input placeholder="WHY NOT FULL WIDTH FOR THIS INPUT BOX?????" class="grow" />
    </span>

    <!-- 4. -->
    <div>
      SECTION-2 --> Maybe right Section
    </div>
  </div>
</div>

For making that input full width add class="w-full" also check if parent span has explicit width specified or defined as block or inline-block in additon to having w-full class. Spans have no default width also are not block nor inline-block elements.

Based on the code you provided, it seems that the input box is contained within a span element with a fixed width set by the p-4 class, which stands for padding: 1rem. This is causing the input box to not take the full width of the parent container.

To make the input box take the full width, you can remove the p-4 class from the span element and add the w-full class to the input element. This will make the input box stretch to fill the available space within its parent container, which has a flex class with "grow" utility, indicating that it should grow to fill any remaining space.

Here's an updated version of your code with these changes applied:

<div class="flex flex-col md:flex-row md:items-center md:justify-between">
  <div class="flex flex-row items-center">
    <div class="icon">ICON</div>
    <div class="brand">BRAND</div>
  </div>
  <div class="flex grow">
    <span class="relative flex w-full items-center bg-green-200">
      <label for="search"></label>
      <div class="icon absolute">ICON</div>
      <input placeholder="WHY NOT FULL WIDTH FOR THIS INPUT BOX?????" class="w-full" />
    </span>
  </div>
  <div class="flex flex-row">SECTION-2</div>
</div>

All divs have display: block by default. Add display: block to the input and it will also become full width.

input {
    display: block;
}

You can also use the block class provided by tailwind