Add day/night button

Author: shuds13

_config.yml

@@ -13,6 +13,7 @@
 # theme                  : "minimal-mistakes-jekyll"
 # remote_theme           : "mmistakes/minimal-mistakes"
 minimal_mistakes_skin    : "default" # "air", "aqua", "contrast", "dark", "dirt", "neon", "mint", "plum", "sunrise"
+minimal_mistakes_skin2   : "dark"
 
 # Site Settings
 locale                   : "en-US"
@@ -166,6 +167,7 @@ footer:
 include:
   - .htaccess
   - _pages
+  - jekyll-include-cache
 exclude:
   - "*.sublime-project"
   - "*.sublime-workspace"

_includes/head.html

@@ -12,7 +12,26 @@
 </script>
 
 <!-- For all browsers -->
-<link rel="stylesheet" href="{{ '/assets/css/main.css' | relative_url }}">
+<link rel="stylesheet" href="{{ '/assets/css/main.css' | relative_url }}" id="theme_source">
+
+{% if site.minimal_mistakes_skin2 %}
+  <link rel="stylesheet alternate" href="{{ '/assets/css/theme2.css' | relative_url }}" id="theme_source_2">
+  <script>
+    let theme = sessionStorage.getItem('theme');
+    if(theme === "dark")
+    {
+      sessionStorage.setItem('theme', 'dark');
+      node1 = document.getElementById('theme_source');
+      node2 = document.getElementById('theme_source_2');
+      node1.setAttribute('rel', 'stylesheet alternate');
+      node2.setAttribute('rel', 'stylesheet');
+    }
+    else
+    {
+      sessionStorage.setItem('theme', 'light');
+    }
+  </script>
+{% endif %}
 
 <!--[if IE ]>
   <style>

_includes/masthead.html

@@ -24,6 +24,11 @@
             </li>
           {%- endfor -%}
         </ul>
+        {% if site.minimal_mistakes_skin2 %}
+          <button type="button" onclick="node1=document.getElementById('theme_source');node2=document.getElementById('theme_source_2');if(node1.getAttribute('rel')=='stylesheet'){node1.setAttribute('rel', 'stylesheet alternate'); node2.setAttribute('rel', 'stylesheet');sessionStorage.setItem('theme', 'dark');}else{node2.setAttribute('rel', 'stylesheet alternate'); node1.setAttribute('rel', 'stylesheet');sessionStorage.setItem('theme', 'light');} return false;">
+          <img class="icon" src="/python-for-hpc//images/day_and_night.svg"></path>
+          </button>
+        {% endif %}
         {% if site.search == true %}
         <button class="search__toggle" type="button">
           <span class="visually-hidden">{{ site.data.ui-text[site.locale].search_label | default: "Toggle search" }}</span>

assets/css/theme2.scss

@@ -0,0 +1,8 @@
+---
+# Only the main Sass file needs front matter (the dashes are enough)
+---
+
+@charset "utf-8";
+
+@import "minimal-mistakes/skins/{{ site.minimal_mistakes_skin2 | default: 'default' }}"; // skin
+@import "minimal-mistakes"; // main partials