Typlog has added a secondary color setting. The original color becomes "primary color". Check out the changes in Settings → Themes & Design:

The primary color and secondary color will be used by theme designers. They are available in css variables:

:root {
  --primary-color-hex: #000;
  --primary-color-rgb: 0,0,0;
  --secondary-color-hex: #000;
  --secondary-color-rgb: 0,0,0;
  --primary-text-rgb: 255,255,255;
  --secondary-text-rgb: 255,255,255;
}

The --{type}-text-rgb is the rgb color that should be used with --{type}-color-hex background. e.g. the background color is in a dark color, therefore the text color should be white.