Text is almost invisible when using RGBA (in dark theme)

[Alyaqdhans]

As the title says the text is unreadable when the color is very transparent:

The text should be aware of the alpha channel in the RGB colors, if it's very transparent the text should be white.

[jasikpark]

Same problem for me using oklch:

It seems to only use black text regardless of the contrast ratio against the color?

[silverwind]

Here are some example values with bad contrast. Basically all low-opacity colors are affected.

  --color-markup-table-row: #e8f3ff0f;
  --color-markup-code-block: #e8f3ff12;
  --color-markup-code-inline: #e8f3ff28;

Also I wonder why it renders two background rectangles, which may be a separate bug.