💄 style: use serif font in body

Also increases the size of the subheader in main page (cards), and
reduces the font weight of links.

sass/main.scss

@@ -1,8 +1,17 @@
 @font-face {
+  /* Copyright 2020 The Inter Project Authors (https://github.com/rsms/inter). Licensed under the SIL Open Font License, Version 1.1. More information available at: http://scripts.sil.org/OFL */
   font-family: 'Inter';
   src: url('fonts/Inter.ttf');
   font-display: swap;
 }
+
+@font-face {
+  /* Copyright 2014, 2015, 2016 Adobe Systems Incorporated (http://www.adobe.com/), with Reserved Font Name 'Source'. Licensed under the SIL Open Font License, Version 1.1. More information available at: http://scripts.sil.org/OFL */
+  font-family: 'Source Serif Pro';
+  src: url('fonts/SourceSerifPro-Regular.ttf');
+  font-display: swap;
+}
+
 @import 'parts/_archive.scss';
 @import 'parts/_cards.scss';
 @import 'parts/_code.scss';
@@ -142,6 +151,11 @@ h5 {
   font-weight: bold;
 }
 
+p {
+  font-family: 'Source Serif Pro', sans-serif;
+  font-size: 1.2em;
+}
+
 img {
   border: none;
 }

sass/parts/_home-banner.scss

@@ -30,6 +30,14 @@
     color: var(--text-color);
 }
 
+#banner-home-subtitle p {
+    font-family: 'Inter', Arial, Helvetica, sans-serif;
+}
+
+#banner-home-subtitle a {
+    font-weight: 400;
+}
+
 .banner-home-img {
     aspect-ratio: 1 / 1;
     max-width: 15rem;

sass/parts/_misc.scss

@@ -46,7 +46,7 @@ blockquote {
 a {
   color: var(--text-color);
   text-decoration-color: var(--links);
-  font-weight: 800;
+  font-weight: 600;
 }
 
 a:hover {