feat(fonts): allow PageTitle to have its own font subset (#1848)

* fix(explorer): vertically center the Explorer toggle under mobile view

* Added a separate title font configuration

* Added googleSubFontHref function

* Applied --titleFont to PageTitle

* Made googleFontHref return array of URLs

* Dealing with empty and undefined title

* Minor update

* Dealing with empty and undefined title

* Refined font inclusion logic

* Adopted the googleFontHref + googleFontSubsetHref method

* Adaptively include font subset for PageTitle

* Restored default config

* Minor changes on configuration docs

* Formatted source code

quartz/plugins/emitters/componentResources.ts

@@ -9,7 +9,12 @@ import styles from "../../styles/custom.scss"
 import popoverStyle from "../../components/styles/popover.scss"
 import { BuildCtx } from "../../util/ctx"
 import { QuartzComponent } from "../../components/types"
-import { googleFontHref, joinStyles, processGoogleFonts } from "../../util/theme"
+import {
+  googleFontHref,
+  googleFontSubsetHref,
+  joinStyles,
+  processGoogleFonts,
+} from "../../util/theme"
 import { Features, transform } from "lightningcss"
 import { transform as transpile } from "esbuild"
 import { write } from "./helpers"
@@ -211,9 +216,16 @@ export const ComponentResources: QuartzEmitterPlugin = () => {
         // let the user do it themselves in css
       } else if (cfg.theme.fontOrigin === "googleFonts" && !cfg.theme.cdnCaching) {
         // when cdnCaching is true, we link to google fonts in Head.tsx
-        const response = await fetch(googleFontHref(ctx.cfg.configuration.theme))
+        const theme = ctx.cfg.configuration.theme
+        const response = await fetch(googleFontHref(theme))
         googleFontsStyleSheet = await response.text()
 
+        if (theme.typography.title) {
+          const title = ctx.cfg.configuration.pageTitle
+          const response = await fetch(googleFontSubsetHref(theme, title))
+          googleFontsStyleSheet += `\n${await response.text()}`
+        }
+
         if (!cfg.baseUrl) {
           throw new Error(
             "baseUrl must be defined when using Google Fonts without cfg.theme.cdnCaching",