docs: polish theme, playground, and reference pages

Improve readability of the docs site with updated light/dark tokens, shared
code-block styling, and playground editors that follow system color scheme.
Skip CookieHub on localhost, serve the browser bundle from theme source, and
use backtick titles on filter/tag reference pages for consistent navigation.

Co-authored-by: Cursor <[email protected]>

docs/scripts/prism-bash-extend.js

@@ -0,0 +1,43 @@
+'use strict'
+
+/**
+ * Extend Prism's bash grammar with extra CLI commands for docs code blocks.
+ * Hexo loads scripts from docs/scripts/ during init, before `hexo generate`
+ * highlights fenced code via syntax_highlighter: prismjs.
+ *
+ * To highlight another command, add its name to EXTRA_BASH_COMMANDS below.
+ */
+const EXTRA_BASH_COMMANDS = [
+  'npx'
+]
+
+const Prism = require('prismjs')
+require('prismjs/components/prism-bash')
+
+function extendBashCommandHighlighting (commands) {
+  const bash = Prism.languages.bash
+  if (!bash || !bash.function) return
+
+  const fnToken = bash.function
+  const pattern = fnToken.pattern
+  if (!(pattern instanceof RegExp)) return
+
+  const source = pattern.source
+  const listMatch = source.match(/\(\?:([^)]+)\)(?=\(\?\=)/)
+  if (!listMatch) return
+
+  const existing = listMatch[1]
+  const toAdd = commands.filter((cmd) => {
+    const re = new RegExp(`(?:^|\\|)${cmd.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}(?:\\||$)`)
+    return !re.test(existing)
+  })
+  if (toAdd.length === 0) return
+
+  const extended = `${existing}|${toAdd.join('|')}`
+  fnToken.pattern = new RegExp(
+    source.replace(/\(\?:([^)]+)\)(?=\(\?\=)/, `(?:${extended})`),
+    pattern.flags
+  )
+}
+
+extendBashCommandHighlighting(EXTRA_BASH_COMMANDS)