make default background darker, remove obsolete replacements

github-dark.user.css

@@ -20138,7 +20138,7 @@
   }
   /* end github.com rules */
   body, body.bg-gray {
-    background-color: #202020 !important;
+    background-color: #141414 !important;
     background-image: var(--bg-img) !important;
     background-clip: border-box !important;
     background-origin: padding-box !important;

src/main.css

@@ -36,7 +36,7 @@
   /* generated github-mobile rules */
   /* generated github.com rules */
   body, body.bg-gray {
-    background-color: #202020 !important;
+    background-color: #141414 !important;
     background-image: var(--bg-img) !important;
     background-clip: border-box !important;
     background-origin: padding-box !important;

tools/build.js

@@ -29,13 +29,6 @@ const sourceFiles = glob("src/*.css").sort((a, b) => {
   if (b.endsWith("base.css")) return 1;
 });
 
-const replacements = [
-  {from: /\/\*\[\[base-color\]\]\*\/ #\w{3,6}/g, to: "/*[[base-color]]*/"},
-  {from: /\/\*\[\[tab-size\]\]\*\/ \d+/g, to: "/*[[tab-size]]*/"},
-  {from: /\/\*\[\[bg-choice\]\]\*\/ url\(.*\)/, to: "/*[[bg-choice]]*/"},
-  {from: "/*[[bg-attachment]]*/ fixed", to: "/*[[bg-attachment]]*/"},
-];
-
 const defaults = {
   theme: "twilight",
   themeCM: "twilight",
@@ -51,13 +44,6 @@ const defaults = {
   tabSizes: [2, 3, 4, 5, 6, 7, 8]
 };
 
-function replaceForUsercss(css) {
-  for (const replacement of replacements) {
-    css = css.replace(replacement.from, replacement.to);
-  }
-  return css;
-}
-
 async function processGroup(css, name) {
   const themes = await getThemesInFolder(name.toLowerCase());
 
@@ -131,7 +117,6 @@ async function main() {
   for (const sourceFile of sourceFiles) {
     let sourceCss = await readFile(sourceFile, "utf8");
     if (sourceFile.endsWith("main.css")) {
-      sourceCss = replaceForUsercss(sourceCss);
       sourceCss = replaceVars(`${themes}${sourceCss}`);
     }