How to add CSS styling to Code Block

Go to your admin dashboard and then click Appearance > Customize Look for the Additional CSS link and click that. Once you have done that copy and paste the code below into your additional CSS box.

pre.wp-block-code {
border-left: 6px solid #3498DB;
background-color: #F5F7F9;
padding: 5px;
}

For an anchor tag the code is:

pre.wp-block-code a {
color: black;
}