Remove 'site url' from theme parameters since it's a site property

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

config.toml

@@ -1,5 +1,4 @@
 [params]
 katexCssUrl = "//static.danilafe.com/katex/katex.min.css"
 normalizeCssUrl = "//static.danilafe.com/normalize/normalize.css"
-siteSourceUrl = "https://dev.danilafe.com/Web-Projects/blog-static/src/branch/master"
 visNetworkJsUrl = "//static.danilafe.com/vis-network/vis-network.min.js"

layouts/partials/defercss.html

@@ -0,0 +1,2 @@
+<link rel="preload" href="{{ .url }}" as="style" onload="this.onload=null;this.rel='stylesheet'" {{ .extra | safeHTMLAttr }}>
+<noscript><link rel="stylesheet" href="{{ .url }}"></noscript>

layouts/partials/head.html

@@ -10,24 +10,32 @@
     <meta name="matrix-highlight-comments" content="{{ . }}">
     {{ end }}
 
+    <!-- Fonts -->
     <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Inconsolata:wght@400;700&family=Raleway&family=Lora&display=block" media="screen">
-    <link rel="stylesheet" href="{{ .Site.Params.normalizeCssUrl }}" media="screen">
-    <link rel="stylesheet" href="{{ .Site.Params.katexCssUrl }}" crossorigin="anonymous">
+
+    <!-- External CSS (normalize and KaTeX -->
+    {{ partial "defercss.html" (dict "url" .Site.Params.normalizeCssUrl "extra" "") }}
+    {{ partial "defercss.html" (dict "url" .Site.Params.katexCssUrl "extra" "crossorigin=\"anonymous\"") }}
+
+    <!-- Links to other formats (RSS, TOML) -->
     {{ range .AlternativeOutputFormats -}}
     <link rel="{{ .Rel }}" type="{{ .MediaType.Type | html }}" href="{{ .Permalink | safeURL }}">
     {{ end -}}
+
+    <!-- In-house CSS -->
     {{ $style := resources.Get "scss/style.scss" | resources.ToCSS | resources.Minify }}
     {{ $sidenotes := resources.Get "scss/sidenotes.scss" | resources.ToCSS | resources.Minify }}
     {{ $code := resources.Get "scss/code.scss" | resources.ToCSS | resources.Minify }}
     {{ $icon := resources.Get "img/favicon.png" }}
     <style>.sidenote-checkbox { display: none; }</style>
     <style>.feather { width: 1rem; height: 1rem; }</style>
-    <link rel="stylesheet" href="{{ $style.Permalink }}" media="screen">
-    <link rel="stylesheet" href="{{ $sidenotes.Permalink }}" media="screen">
-    <link rel="stylesheet" href="{{ $code.Permalink }}" media="screen">
+    <link rel="stylesheet" href="{{ $style.Permalink }}">
+    {{ partial "defercss.html" (dict "url" $sidenotes.Permalink "extra" "") }}
+    {{ partial "defercss.html" (dict "url" $code.Permalink "extra" "") }}
     <link rel="icon" type="image/png" href="{{ $icon.Permalink }}">
 
     {{ if .Site.IsServer }}
+    <!-- KaTeX auto-rendering for when we don't have a post-processing step. -->
     <script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.0/dist/katex.min.js" integrity="sha384-X/XCfMm41VSsqRNQgDerQczD69XqmjOOOwYQvr/uuC+j4OPoNhVgjdGFwhvN02Ja" crossorigin="anonymous"></script>
     <script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.0/dist/contrib/auto-render.min.js" integrity="sha384-+XBljXPPiv+OzfbB3cVmLHf4hdUFHlWNZN5spNQ7rmHTXpd7WvJum6fIACpNNfIR" crossorigin="anonymous"
         onload="renderMathInElement(document.body);"></script>