Reply To: Customizating the individual blog post view

[Andy]

This Additional CSS will remove the heading underlines:

#comments h3.comment-reply-title:before,
.related-posts h3:before {
    background: transparent;
}

The author section already has border radius to the top left and right corners, and padding. To make all four corners rounded, add this Additional CSS:

.single .entry-footer {
    border-radius: 2rem;
}