title: Bootstrap 4 custom file upload and sizing
body: <p>How can I add custom file input sizing to Bootstrap 4 by using the classes such as <code>input-group-sm</code>, <code>form-control-sm</code> etc..? I want to set this custom file input field as small. Does anyone have a solution?</p>
  <h3>Using class <code>form-control-sm</code></h3>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet"/&gt;
  
      &lt;div class="form-group"&gt;
        &lt;input class="form-control form-control-sm" value="Small input field"&gt;
      &lt;/div&gt;</code></pre>
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  </p>
  <h3>Using class <code>input-group-sm</code></h3>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet"/&gt;
  
  &lt;div class="input-group input-group-sm"&gt;
    &lt;div class="input-group-prepend"&gt;
      &lt;span class="input-group-text"&gt;Go&lt;/span&gt;
    &lt;/div&gt;
    &lt;input type="text" class="form-control" id="basic-url" aria-describedby="basic-addon3" value="Small input group"&gt;
  &lt;/div&gt;</code></pre>
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  <h3>Both are NOT WORKING here. How can I make the <strong>input field small</strong>?</h3>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet"/&gt;
  
  &lt;div class="input-group input-group-sm"&gt;
    &lt;div class="custom-file"&gt;
      &lt;input type="file" class="custom-file-input form-control-sm"&gt;
      &lt;label class="custom-file-label"&gt;Choose file&lt;/label&gt;
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
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  </p>