Actually, your green line is a green "border-top". If you want them with the same color we should replace the "hr" with a div and give them the same class.
1- Creating the class in your css:
.harvey_line {
border-top:1px solid #D1CF92" !important
}
2- Editing root_post_message:
go to your root_post_message macro and remove border property from this line and add the class:
<div class="classic-row" style="margin:1.5em .4em;border-top:1px solid #D1CF92">
like this:
<div class="classic-row harvey_line" style="margin:1.5em .4em>
Now, instead of use "hr" tag, you should use an empty div like this:
<div class="harvey_line"></div>
Let me know if you have any issues.