Solved yellow lines in construction

For CTA, it's separated into 3 parts:

1. Title
2. Content
3. Button

For this case, we don't use the button part.
1. Title
2. Content

Title don't accept HTML coding in it, so we use the content to insert the yellow lines.

So, at the top of the content, we add the yellow line HTML & CSS, so that it will show right below the title.
<div class="free-header-border-bottom" style="height: 3px;width: 80px;margin: 32px 0 20px 0!important;"></div>

And for the content, we put it right below the yellow line HTML. Remember to use p tag so that your content will be full width, and will not be affected by the yellow line.
**Cause the yellow line is using display: inline-block; & your content will continue at the end of the yellow line if you didn't use p tag.
<p>Your Content</p>

So, the end result is that the yellow line is between the Title & Content.

 

For v3.0 & above, you just need to go to Theme Customizer -> Divi Ultimate -> Global Styling -> Header Border Color