Currently the top bar background is #0b4141 (Deep Teal).
So, I'm testing a border in #E2725B (Terracotta) surrounding the reading panel, making it a classic “earth and sea” pairing.
And because they are nearly complementary (sitting opposite each other on the color wheel), they create a natural visual vibration that feels balanced—the warmth of the Terracotta cuts through the coolness of the Teal without being as “loud” as a bright orange or red.
Vibe: It leans into a “Modern Organic” or “Mid-Century” aesthetic that feels high-end and intentional.
Next, the Table of Contents for the article's sidebar was calling for a redish H3.
I've chosen the Valencia saturated, spicy red #D04436. Valencia has enough orange in its DNA to harmonize with the terracotta background on the H1 article title.
It's visual continuity because Valencia is essentially a more intense, darker version of Terracotta, the transition from the main title background to the TOC feels intentional and high-end.
Also, legibility is good as it doesn't glow. see here .