refactor: [slides] Move slides styles into scss

Remove styles from 'slides/style.html' and move them into SASS partial
'styles/_slides.scss'. Import the partial in 'styles/app.scss'.

Author: manid2

assets/styles/_slides.scss

@@ -0,0 +1,31 @@
+:root {
+  --r-background-color: #{$background--light};
+  --r-code-font: #{$font-family-mono};
+  --r-heading-color: #{$text--light};
+  --r-heading-font: #{$font-family-title};
+  --r-link-color: #{$text-links--light};
+  --r-main-color: #{$text--light};
+  --r-main-font-size: #{$font-size};
+  --r-main-font: #{$font-family-normal};
+}
+
+.reveal {
+  width: 100%;
+  height: $spacer-large * 25;
+}
+
+.header-left,
+.footer-left {
+  position: absolute;
+  left: 0%;
+  margin: $spacer-large;
+  padding: $spacer-small;
+}
+
+.header-left {
+  top: 0%;
+}
+
+.footer-left {
+  bottom: 0%;
+}

assets/styles/app.scss

@@ -13,3 +13,4 @@
 /* code syntax highlight */
 @import "gen_syntax";
 @import "syntax";
+@import "slides";

layouts/partials/slides/style.html

@@ -1,51 +1,3 @@
 <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/reveal.js/4.4.0/reveal.min.css" />
 <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/reveal.js/4.4.0/theme/black.min.css" id="theme" />
 <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/reveal.js/4.4.0/plugin/highlight/monokai.min.css" />
-
-<style type="text/css">
-  :root {
-    --r-background-color: rgb(29, 33, 44);
-    --r-main-color: aqua;
-    --r-heading-color: aqua;
-    --r-heading-text-transform: none;
-    --r-main-font-size: 1.2em;
-    --r-main-font: Arial, Helvetica, Verdana, sans-serif;
-    --r-heading-font: "Times New Roman", Garamond, Georgia, serif;
-    --r-code-font: "Ubuntu mono", "Fira code", monospace;
-    --r-selection-color: white;
-    --r-selection-background-color: blue;
-    --r-link-color: lightgreen;
-    --r-link-color-hover: magenta;
-  }
-
-  code,
-  kbd {
-    color: #23b0ff;
-    background: rgba(35, 176, 255, 0.2);
-    padding: 1px 6px;
-    margin: 0 2px;
-  }
-
-  .header-left {
-    position: absolute;
-    top: 0%;
-    left: 0%;
-    margin: 20px;
-    padding: 10px;
-  }
-
-  .footer-left {
-    position: absolute;
-    bottom: 0%;
-    left: 0%;
-    margin: 20px;
-    padding: 10px;
-  }
-
-  @media print {
-    @page {
-      size: A4 landscape;
-      margin: 1in;
-    }
-  }
-</style>