bootstrap bg gray code example

Example 1: bootstrap text color

<p class="text-primary">.text-primary</p>
<p class="text-secondary">.text-secondary</p>
<p class="text-success">.text-success</p>
<p class="text-danger">.text-danger</p>
<p class="text-warning">.text-warning</p>
<p class="text-info">.text-info</p>
<p class="text-light bg-dark">.text-light</p>
<p class="text-dark">.text-dark</p>
<p class="text-muted">.text-muted</p>
<p class="text-white bg-dark">.text-white</p>

Example 2: bootstrap 4 text color

<p class="text-primary">Text with primary color</p>
<p class="text-secondary">Text with secondary color</p>
<p class="text-success">Text with success color</p>
<p class="text-danger">Text with danger color</p>
<p class="text-warning">Text with warning color</p>
<p class="text-info">Text with info color</p>
<p class="text-light bg-dark">Text with light color</p>
<p class="text-dark">Text with dark color</p>
<p class="text-muted">Text with muted color</p>
<p class="text-white bg-dark">Text with white color</p>

Example 3: bootstrap color a div

use something like :
<div class="container alert alert-success">
   <div class="row">
      <div class="col">I'm your content inside the grid!</div>
   </div>
</div>

Example 4: change bootstrap background color

<style type="text/css">
   body { background: navy !important; } /* Adding !important forces the browser to overwrite the default style applied by Bootstrap */
</style>