bootstrap override css
<!---------------- How do I override Bootstrap CSS? ------------------->
If your custom styles are not overriding the bootstrap styles, all you
need to do is move the link to your custom stylesheet to a line after
the bootstrap link:
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet">
<link rel="stylesheet" href="styles.css">
This means that you first load the default bootstrap styles, then you
can override some of those components with your own custom CSS.