chore: split out styles + only load where needed

src/pages/about.md

@@ -3,6 +3,12 @@ title: About
 layout: default
 permalink: /about.html
 ---
+{% capture css %}
+  {% render "../assets/styles/pages/about.css" %}
+{% endcapture %}
+<style>
+  {{ css | cssmin }}
+</style>
 <div class="avatar__wrapper flex--centered">
   <div class="avatar__wrapper--interior">
     {% capture about_alt %}{{ meta.siteName }} - image by David Neal / @reverentgeek{% endcapture %}