You could use hi-lock-mode to define your own colouring for such lines. But I'm sure those that under font-locking better might be able to add appropriate rules for this horizontal line construct.
-- : Eric S Fraga via Emacs 28.0.50, Org 9.5-g9a4a24 : Latest paper written in org: https://arxiv.org/abs/2106.05096
