Use pst-color-background instead of colorBackground

perl -pi -e  's:var\(\-\-colorBackground\):var(\-\-pst\-color\-background\):g' assets/theme-css/styles.css
sed -i '/\-\-colorBackground\: /d' assets/theme-css/light-mode.css
sed -i '/\-\-colorBackground\: /d' assets/theme-css/dark-mode.css

Author: jarrodmillman

assets/theme-css/dark-mode.css

@@ -3,7 +3,6 @@
     /* Basically, we reassign the colors named in the non-dark theme. The
        exception is the background: it seems to look better as #111
        than as --colorPrimaryDark. */
-    --colorBackground: #111;
     --colorBackgroundAlt: var(--colorPrimaryDark);
     --colorBackgroundAlt2: var(--colorSecondaryDark);
 

assets/theme-css/light-mode.css

@@ -1,7 +1,6 @@
 @media not (prefers-color-scheme: dark) {
   :root {
     /* Now we assign those named colors to various purposes. */
-    --colorBackground: var(--colorSecondaryLight);
     --colorBackgroundAlt: var(--colorPrimaryDark);
     --colorBackgroundAlt2: var(--colorSecondaryDark);
 

assets/theme-css/styles.css

@@ -309,7 +309,7 @@ svg.icon {
 
 nav,
 .navbar {
-  background: var(--colorBackground);
+  background: var(--pst-color-background);
   color: var(--pst-color-text-base);
 }
 .navbar-burger {