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/components/Head.tsx

@@ -1,7 +1,7 @@
 import { i18n } from "../i18n"
 import { FullSlug, getFileExtension, joinSegments, pathToRoot } from "../util/path"
 import { CSSResourceToStyleElement, JSResourceToScriptElement } from "../util/resources"
-import { googleFontHref } from "../util/theme"
+import { googleFontHref, googleFontSubsetHref } from "../util/theme"
 import { QuartzComponent, QuartzComponentConstructor, QuartzComponentProps } from "./types"
 import { unescapeHTML } from "../util/escape"
 import { CustomOgImagesEmitterName } from "../plugins/emitters/ogImage"
@@ -45,6 +45,9 @@ export default (() => {
             <link rel="preconnect" href="https://fonts.googleapis.com" />
             <link rel="preconnect" href="https://fonts.gstatic.com" />
             <link rel="stylesheet" href={googleFontHref(cfg.theme)} />
+            {cfg.theme.typography.title && (
+              <link rel="stylesheet" href={googleFontSubsetHref(cfg.theme, cfg.pageTitle)} />
+            )}
           </>
         )}
         <link rel="preconnect" href="https://cdnjs.cloudflare.com" crossOrigin="anonymous" />

quartz/components/PageTitle.tsx

@@ -17,6 +17,7 @@ PageTitle.css = `
 .page-title {
   font-size: 1.75rem;
   margin: 0;
+  font-family: var(--titleFont);
 }
 `