Replace the Noto fonts with good-enough font stacks

They're heavy and take time to load! It's more noticeable on such a
text-heavy page as this, too.

I might make a similar change on DTI… I had used these fonts here for
visual consistency, but tbh I'm not sure these fonts are notably better
than the system fonts anyway! And our brand identity isn't hinged on
them. (Whereas I *did* keep the Delicious fonts, because the files are
notably smaller, and they *are* more part of our visual identity, I
think.)

assets/css/main.css

@@ -1,5 +1,12 @@
+:root {
+	/* Thanks to! https://modernfontstacks.com/ */
+	--ui-font-family: system-ui, sans-serif;
+	--heading-font-family: Delicious, system-ui, sans-serif;
+	--body-font-family: Charter, "Bitstream Charter", "Sitka Text", Cambria, serif;
+}
+
 body {
-	font-family: "Noto Sans", Helvetica, Arial, Verdana, sans-serif;
+	font-family: var(--ui-font-family);
 	color: #040;
 	max-width: 800px;
 	margin-inline: auto;
@@ -16,7 +23,7 @@ h3,
 h4,
 h5,
 h6 {
-	font-family: Delicious, "Noto Sans", Helvetica, Arial, Verdana, sans-serif;
+	font-family: var(--heading-font-family);
 
 	a {
 		color: inherit;
@@ -84,7 +91,8 @@ article {
 	}
 
 	> :is(p, ul) {
-		font-family: "Noto Serif", Georgia, "Times New Roman", Times, serif;
+		font-family: var(--body-font-family);
+		line-height: 1.4;
 	}
 
 	h3 {
@@ -129,25 +137,3 @@ article {
 	font-style: italic;
 	src: local("Delicious"), url("/assets/fonts/Delicious-Italic.otf");
 }
-
-@font-face {
-	font-family: "Noto Sans";
-	src: local("Noto Sans"), url("/assets/fonts/NotoSans-Variable.ttf");
-}
-
-@font-face {
-	font-family: "Noto Sans";
-	font-style: italic;
-	src: local("Noto Sans"), url("/assets/fonts/NotoSans-Italic-Variable.ttf");
-}
-
-@font-face {
-	font-family: "Noto Serif";
-	src: local("Noto Serif"), url("/assets/fonts/NotoSerif-Variable.ttf");
-}
-
-@font-face {
-	font-family: "Noto Serif";
-	font-style: italic;
-	src: local("Noto Serif"), url("/assets/fonts/NotoSerif-Italic-Variable.ttf");
-}