hugo-theme-relearn/assets/css/theme-zen-dark.css

:root {
  --PRIMARY-color: rgba(47, 129, 235, 1); /* brand primary color */
  --SECONDARY-color: rgba(47, 129, 235, 1); /* brand secondary color */

  --MAIN-TOPBAR-BORDER-color: rgba(71, 71, 71, 1); /* border color between topbar and content */
  --MAIN-LINK-HOVER-color: rgb(112, 174, 245); /* hovered link color of content */
  --MAIN-BG-color: rgba(32, 32, 32, 1); /* background color of content */
  --MAIN-TEXT-color: rgba(224, 224, 224, 1); /* text color of content and h1 titles */
  --MAIN-TITLES-TEXT-color: rgba(255, 255, 255, 1); /* text color of h2-h6 titles and transparent box titles */

  --CODE-theme: relearn-dark; /* name of the chroma stylesheet file */
  --CODE-BLOCK-color: rgba(248, 248, 242, 1); /* fallback text color of block code; should be adjusted to your selected chroma style */
  --CODE-BLOCK-BG-color: rgba(43, 43, 43, 1); /* fallback background color of block code; should be adjusted to your selected chroma style */
  --CODE-BLOCK-BORDER-color: rgba(71, 71, 71, 1); /* border color of block code */
  --CODE-INLINE-color: rgba(130, 229, 80, 1); /* text color of inline code */
  --CODE-INLINE-BG-color: rgba(45, 45, 45, 1); /* background color of inline code */
  --CODE-INLINE-BORDER-color: rgba(71, 71, 71, 1); /* border color of inline code */

  --BROWSER-theme: dark; /* name of the theme for browser scrollbars of the main section */
  --MERMAID-theme: dark; /* name of the default Mermaid theme for this variant, can be overridden in hugo.toml */
  --OPENAPI-theme: dark; /* name of the default OpenAPI theme for this variant, can be overridden in hugo.toml */
  --OPENAPI-CODE-theme: obsidian; /* name of the default OpenAPI code theme for this variant, can be overridden in hugo.toml */

  --MENU-BORDER-color: rgba(71, 71, 71, 1); /* border color between menu and content */
  --MENU-TOPBAR-BORDER-color: rgba(39, 39, 39, 1); /* separator color of vertical line between menu and topbar */
  --MENU-TOPBAR-SEPARATOR-color: rgba(71, 71, 71, 1); /* separator color of vertical line between menu and topbar */
  --MENU-HEADER-BG-color: transparent; /* background color of menu header */
  --MENU-HEADER-BORDER-color: transparent; /* border color between menu header and menu */
  --MENU-HEADER-SEPARATOR-color: rgba(71, 71, 71, 0.66); /* separator color between menu header and menu */

  --MENU-HOME-LINK-color: rgba(224, 224, 224, 1); /* home button color if configured */
  --MENU-HOME-LINK-HOVER-color: rgba(47, 129, 235, 1); /* hovered home button color if configured */

  --MENU-SEARCH-color: rgba(47, 129, 235, 1); /* text and icon color of search box */
  --MENU-SEARCH-BG-color: rgba(32, 32, 32, 1); /* background color of search box */
  --MENU-SEARCH-BORDER-color: rgba(71, 71, 71, 0.66); /* border color of search box */

  --MENU-SECTIONS-BG-color: rgba(39, 39, 39, 1); /* background of the menu; this is NOT just a color value but can be a complete CSS background definition including gradients, etc. */
  --MENU-SECTIONS-ACTIVE-BG-color: transparent; /* background color of the active menu section */
  --MENU-SECTIONS-LINK-color: rgba(224, 224, 224, 0.75); /* link color of menu topics */
  --MENU-SECTIONS-LINK-HOVER-color: rgba(47, 129, 235, 1); /* hoverd link color of menu topics */
  --MENU-SECTION-ACTIVE-CATEGORY-color: rgba(47, 129, 235, 1); /* text color of the displayed menu topic */
  --MENU-SECTION-ACTIVE-CATEGORY-BG-color: rgba(32, 32, 32, 1); /* background color of the displayed menu topic */
  --MENU-SECTION-SEPARATOR-color: rgba(71, 71, 71, 0.66); /* separator color between menu sections and menu footer */

  --BOX-CAPTION-color: rgba(240, 240, 240, 1); /* text color of colored box titles */
  --BOX-BG-color: rgba(20, 20, 20, 1); /* background color of colored boxes */
  --BOX-TEXT-color: rgba(224, 224, 224, 1); /* text color of colored box content */

  --BOX-GREY-color: rgba(71, 71, 71, 1); /* background color of grey boxes */
}

body a#R-logo,
body a#R-logo:hover,
body #R-logo svg,
body #R-logo svg * {
  color: var(--MENU-HOME-LINK-color);
  fill: var(--MENU-HOME-LINK-color) !important;
}